Ground fissure development regularity and formation mechanism of shallow buried coal seam mining with Karst landform in Jiaozi coal mine: a case study

A comprehensive study was undertaken at Jiaozi coal mine to investigate the development regularity of ground fissures in shallow buried coal seam mining with Karst landform,shedding light on the development type,geographical distribution,dynamic development process,and failure mechanism of these ground fissures by employing field monitoring,numerical simulation,and theoretical analysis.The findings demonstrate that ground fissure development has an obvious feature of subregion,and its geographical distribution is significantly affected by topography.Tensile type,open type,and stepped type are three different categories of ground fissure.Ground fissures emerge dynamically as the panel advances,and they typically develop with a distance of less than periodic weighting step distance in advance of panel advancing position.Ground fissures present the dynamic development feature,temporary fissure has the ability of self-healing.The dynamic development process of ground fissure with closed-distance coal seam repeated mining is expounded,and the development scale is a dynamic development stage of“closure→expansion→stabilized”on the basis of the original development scale.From the perspective of topsoil deformation,the computation model considering two points movement vectors towards two directions of the gob and the ground surface is established,the development criterion considering the critical deformation value of topsoil is obtained.The mechanical model of hinged structure of inclined body is proposed to clarify the ground fissure development,and the interaction between slope activity and ground fissure development is expounded.These research results fulfill the gap of ground fissures about development regularity and formation mechanism,and can contribute to ground fissure prevention and treatment with Karst landform.

Study of the Conditions of Formation and Forecast of the Perspective Areas of Hydrogen-Sulfide Water of Surkhandarya Depression

Increase in requirement of hydrosulphuric water for improvement of the population set the task of identification of places of their possible congestion for hydrogeological service. Earlier detection of such congestions was accidental at well-drilling of different function. Therefore, development of new methodical approaches of search and allocation of perspective zones of their formation was required. It was for this purpose necessary to study in what conditions and what factors have an impact on formation of underground hydrosulphuric water. So far, definition of communication attempts only with separate geochemical signs was known. Results of studying of influence on formations of hydrosulphuric water of such factors as lithologic and facial in combination with oil-and-gas content, the geological and structural and hydrodynamic mode are given in this work. It is established that the main sign for formation of hydrosulphuric water is existence of evaporite thickness and hydrocarbon congestions. Besides, it is shown that small depth (up to 2 km) of their bedding has to be an indispensable condition and existence of explosive violation on which there has to be a water infiltration (a geological and structural factor). In the Surkhandarya region, the hydrodynamic mode caused by inclined bedding of aquifers was also one of essential factors. Active water is an exchange process with washing away (oxidation) sulfate of the containing thicknesses and subsequently, its restoration in interaction with hydrocarbons with formation of hydrosulphuric water is described. The technique is developed and the expected card of perspective zones of formation of hydrosulphuric water is constructed.

基于图和流体扰动算法的多无人车编队及避障研究

为解决多无人车编队在存在运动目标、移动威胁与突发威胁等多种情况的复杂环境中的避障问题,设计了一种基于刚性图论和流体扰动算法的多无人车编队避障控制算法。首先,针对编队控制问题,采用图论方法描述多无人车之间的协同关系,利用无人车之间的距离约束,基于反步控制理论设计领航-跟随编队控制器。李雅普诺夫分析表明,期望的编队形状是渐近稳定的。其次,针对复杂动态障碍物环境下的编队避障问题,设计了基于流体扰动算法的避障路径规划方法,由领航无人车规划出编队的行驶路径,实现编队的整体避障。最后,基于MATLAB的仿真结果验证了所提算法的有效性。

黄河泛滥平原第四系地面塌陷机理研究--以菏泽市牡丹区为例

本文以菏泽市牡丹区地质灾害风险普查为依托,从牡丹区已发生的24处第四系地面塌陷中选取9处塌陷点进行分析,并优选了1处塌陷通过高密度电阻率法、地质雷达、钻探、原位测试、分析化验等方法对其形成机理进行了研究。通过综合物探查出视电阻率低阻异常区,在异常区经钻探验证,并取样分析,在原塌陷坑处的物理力学性质明显比周围差。经研究分析可知:第四系地面塌陷的主要原因是由于原地下存在着建(构)筑物,当发育于全新世的黄河古河道改道时,掩埋了原建(构)筑物,形成了空洞,当受到地下水位波动频繁等外力作用时,打破了古建(构)筑物的应力平衡,当持力层遭到破坏后,便发生了第四系地面塌陷。

媒体朝圣与网红旅游目的地的形成机制——基于淄博和哈尔滨的扎根理论分析

文章综合使用双案例研究和扎根理论方法对淄博和哈尔滨进行探索式理论建构,发现:第一,淄博作为一个老工业城市,其旅游资源相对匮乏,构建旅游品牌相对困难,此次走红完全是游客在社交媒体自发传播的产物,属于自发型走红,具有很大的偶然性。第二,哈尔滨旅游资源丰富且具有一定的旅游发展基础,当地相关部门凭借资源优势,主动策划并提前准备预热,属于“设计型+自发型”走红。第三,网红旅游目的地作为信息传播、文化表达和消费趋势的交汇点,其走红初期必然遵循“自组织”或“建构型”的流量撬动模式。然而随着旅游目的地的出圈以及游客群体的不断增长,初期以旅游者或目的地参与主体的单方流量撬动型不足以维系网红旅游目的地的生命力。相反,旅游者和目的地参与主体双方共同在媒介空间中进行“多向度、发散式”的互动传播才是旅游目的地持续走红的关键。

领导干部“能上不能下”制度困境的形成机理与破解之道

本文以83名领导干部的访谈内容为研究样本,运用扎根理论,识别出影响领导干部“能上不能下”的因素主要包含实施主体、实施对象、制度本身和运行环境四个维度。具体来说:实施主体在推进干部能上能下过程中出现执行乏力问题;实施对象受到趋利避害的个人偏好的驱动和影响;制度本身存在着操作性障碍;蕴含于特定政治生态环境中的消极因素也成为领导干部“能下”的阻力。相应地提出破解领导干部“能上不能下”制度困境的因应之策:着力提高组工干部队伍的专业化能力,解决好实施主体执行乏力问题;进一步提升广大领导干部的担当精神与大局意识,解决实施对象利己偏好的问题;完善长效化协同化的制度体系,解决制度操作性障碍的问题;不断引导全社会形成包容开放的文化氛围,解决运行环境压力渗透的问题。

基于层级结构的空−地协同预设时间最优容错控制

研究了发生执行器故障的无人机−无人车异构编队系统的层级预设时间最优编队控制问题.以保容错性能和收敛速度的优化控制为研究主线,以层级控制、图博弈理论和预设时间控制为技术基础,构建了一种预设时间最优容错控制算法.虚拟层设计了基于一致性跟踪误差和能量消耗的二次型性能指标函数,借助耦合哈密顿−雅克比−贝尔曼(Hanmilton-Jacobi-Bellman,HJB)方程和强化学习求解近似最优控制策略,实现多智能体的同步最优控制和交互纳什均衡.实际控制层基于最优信号并利用滑模控制和自适应技术,设计了预设时间容错跟踪控制器,实现对最优编队轨迹的有限时间跟踪.在保证全局收敛时间完全不依赖于系统的初始状态和控制器参数的同时,也有效实现对执行器故障参数的逼近.最后,通过仿真实验验证了所提控制策略的有效性.

基于扎根理论的基层疾病预防控制人员职业倦怠发生机制探析

目的探讨基层疾病预防控制人员职业倦怠的发生机制,对加强和改善疾病预防控制工作提供相关支撑。方法2023年7月17日至20日,选取深圳市宝安区疾病预防控制中心、公共卫生服务中心、3家公共卫生服务街道分中心、1家社区医院、1家社区健康服务中心、1家社区健康服务站作为访谈单位,以目的抽样法在访谈单位中选取20名基层疾病预防控制人员进行半结构化访谈,利用Nvivo11质性分析软件对访谈资料进行处理,通过扎根理论三级编码提炼相关概念和范畴。结果梳理出初始概念32个、范畴15个、主范畴7个,构建了包含管理机制、工作维度、个人维度、体系建设和社会地位5个核心类属在内的基层疾病预防控制人员职业倦怠发生机制模型。结论管理机制、工作维度、体系建设和社会地位直接或间接对个人维度产生影响,引起职业倦怠的综合反应。应稳步推进疾病预防控制体系建设向纵深发展,健全疾病预防控制管理机制,加强对疾病预防控制工作的宣传普及,以缓解基层疾病预防控制机构人员职业倦怠,促进其职业健康。

2019年湖南攸县7·15大型岩溶地面塌陷的发育分布规律及形成机理

2019年7月15日,湖南株洲市攸县樟井村发生大规模岩溶地面塌陷,严重威胁当地人民群众的生命和财产安全。为查明7·15大型岩溶地面塌陷的形成机理,通过地球物理勘探、水文地质工程地质钻探、地下水监测、水化学分析等多种手段对岩溶地面塌陷区开展了详细的调查研究,分析了该岩溶地面塌陷的发育规律及致灾因素。结果表明:7·15大型岩溶地面塌陷是由降雨主导,在地表覆盖层软化减强、岩溶气爆和渗流潜蚀效应等多种不良因素共同作用诱发的自然塌陷;地面塌陷位于断层、褶皱等构造密集发育的可溶性碳酸盐岩区域,区内岩溶强烈,广泛发育的溶洞、落水洞、泉、地下暗河等岩溶形迹为地面塌陷的形成提供了条件;7·15大型岩溶地面塌陷的形成演化可分为降雨诱发的地表覆盖层土体软化减强和封盖增荷、降雨导致地下水水位上升引发的岩溶气爆、地下水渗流潜蚀加速顶板垮塌形成土洞、土洞扩大及顶板失稳4个阶段。该研究结果可为类似地质条件地区的岩溶地面塌陷预测预报与防治提供科学依据。

中国男足球员职业污名形成机制——基于扎根理论的探索性研究

该研究运用污名化、第三人效应和场域等理论,深度剖析了由“冯巩大战”引发的中国男足球员职业污名现象,构建了由热点事件、应激反应、公众楷模、社会认知等17个范畴以及负面刻板印象、媒体舆论导向、球员生存场域、社会化程度4个主范畴组成的中国男足球员职业污名形成机制理论模型。研究发现:原本就固化于公众心目中的中国男足球员负面刻板印象,经媒体对热点事件的炒作后再次得到加强,并使公众产生相应的负面情绪,当负面情绪遇到球员的“回怼”时,中国男足球员职业污名已不可避免,球员愈想正名愈发污名。研究认为:中国男足球员职业污名既反映了公众对球员的失望和愤怒,亦深层次折射了公众对中国足球理性认知的缺乏,更是当前中国足球社会化程度偏低的现实呈现。研究建议:球员应提升自身的竞技能力,展现拼搏精神,承担社会责任;加强自媒体监管和规范,提倡正向评论,避免夸大负面事件;确保球员权益和利益受到保障,鼓励球员-媒体共生,增强球员心理韧性;建立行业自律,惩戒违规行为,重视足球文化建设。

Atomistic understanding of capacity loss in LiNiO_(2)for high-nickel Li-ion batteries:First-principles study

Combining the first-principles calculations and structural enumeration with recognition,the delithiation process of LiNiO_(2)is investigated,where various supercell shapes are considered in order to obtain the formation energy of Li_(x)NiO_(2).Meanwhile,the voltage profile is simulated and the ordered phases of lithium vacancies corresponding to concentrations of 1/4,2/5,3/7,1/2,2/3,3/4,5/6,and 6/7 are predicted.To understand the capacity decay in the experiment during the charge/discharge cycles,deoxygenation and Li/Ni antisite defects are calculated,revealing that the chains of oxygen vacancies will be energetically preferrable.It can be inferred that in the absence of oxygen atom in high delithiate state,the diffusion of Ni atoms is facilitated and the formation of Li/Ni antisite is induced.

基于扎根理论的上海红色旅游形象感知影响因素与形成机理研究

以上海28个红色旅游景点为研究对象,基于游客在线评论数据,运用内容分析和扎根理论对红色旅游形象感知内容特征、影响因素、形成机理进行了系统性的研究。结果表明:扎根理论分析得到红色旅游形象感知影响因素包括媒体渠道、旅游经验、出游目的等24个要素,可归纳为信息来源、个体因素、核心吸引物等7个维度,并基于游前、游中、游后的时间线索提取出原生/引致形象、复合形象、评判形象3个层次,构建了红色旅游形象感知形成机理模型。依据研究结果,提出上海红色旅游形象分阶段塑造与传播的对策建议。

山东鲁西北地区馆陶组热储及流体化学特征

鲁西北地热区热储主要为层状热储,地温相对于其它地热区均匀,具有较高的热流值和富水性较强的含水层,是山东省地热资源开发潜力最大的地区。鲁西北地区的主要热储之一为新近系馆陶组孔隙裂隙热储层组。研究发现其上部地层发育细—中粒砂岩及泥岩与细粒砂岩互层夹粉砂岩;下部地层发育中细粒砂岩、中粒砂岩及砂砾岩夹泥岩;新近系馆陶组热储层具有顶底板埋深自南向北由浅变深、厚度由薄变厚,在凸起区埋藏浅、厚度薄,凹陷区埋藏深、厚度大等变化规律;地热水化学特征在水平方向具有以下分布特征:水化学类型由南部、东南部的SO_(4)·Cl-Na型向北、西北逐渐过渡为Cl·SO_(4)-Na型至Cl-Na。

动态可重构自适应无人车辆编队系统

为研究无人车编队系统的编队保持、队形重构及队形变换功能,提出一种混合式领航跟随策略,以降低对领航车的依赖并确保编队完整性。开发基于车间(Vehicle to Vehicle,V2V)通信的跟随车独立避障功能,并设计了实时管理编队成员属性并支持人机交互的编队节点管理系统。提出一种三维空间下的三次样条曲线动态扩展轨迹规划方法,结合V2V通信获取前车位姿信息生成跟随轨迹并实现避障。利用Frenet坐标系解耦车距保持与轨迹跟踪问题,采用PID控制器和线性二次调节(Linear Quadratic Regulator,LQR)控制器分别进行纵向控制和横向轨迹跟踪。研究结果表明:所搭建的仿真环境可快速验证方法性能,显示该方法具有良好的性能;通过实车验证了车辆编队系统的3种功能,通过车距稳定保持,证实所提方法具备良好实时性,能够实现多车编队的有效跟随,通过多种队形的变换以及成员入队离队场景,显示出高度的智能拓展性和适应性。

基于鸽群优化改进动态窗的多无人车协同编队避障控制

在复杂未知的战场环境中,无人车集群较单台无人车可承担更为复杂的任务,无人车集群协同编队避障行驶是群体智能领域研究热点之一.针对未知环境下无人车集群在规避障碍物时容易出现动态位置与预期队形偏差较大问题,本文提出了一种基于改进动态窗的无人车编队协同避障控制方法,在基本动态窗路径评价函数的方位角评价因子、障碍物评价因子、速度评价因子基础上,增加了无人车编队的方向协同因子和队形保持因子.同时,基于变权重鸽群优化算法对改进动态窗的路径评价函数各系数进行优化.当无人车集群感知到障碍物时,通过改进动态窗算法进行相对位置及速度的自适应协同调整,更好地保证无人车编队避障行驶过程中队形位置的精确性.最后,以3台无人车构成三角形编队避障行驶为例进行仿真验证.仿真结果表明基于改进动态窗和变权重鸽群优化算法的无人车编队在规避障碍物时,队形位置偏差相对较小.可见,本文提出的改进算法能够使得无人车集群在规避障碍物过程中提高动态编队的稳定性和精确性.

执行器故障下无人机无人车异构编队控制

针对存在执行器故障的无人机无人车异构系统,研究了编队跟踪容错控制问题。首先,异构系统采用有向图的拓扑结构,且并非所有无人机/车都能接收到参考信号,故在充分考虑无人机/车运动学模型存在较大差异的前提下,设计了一种针对两类系统都通用的分布式信号估计器来获取参考信号的信息。然后,基于参考信号估计值,利用鲁棒自适应控制理论,提出了形式统一的分布式容错控制协议。该协议无需获取精准故障信息,就能有效地补偿故障对异构系统性能的影响,确保异构系统在故障情况下仍能按照预先设定的编队构型跟踪上外界参考信号。最后,通过仿真试验验证了所提算法的有效性。

个体为何信任生成式人工智能?——一项基于扎根理论的质性研究

在当前智能媒介技术快速发展的背景下,生成式人工智能作为推动社会变革的关键力量,正引发全球范围内对其信任问题的深入探讨。本文采用扎根理论方法,从个体视角出发,通过对“知乎”平台上关于ChatGPT的评论数据进行质性分析,旨在理解影响个体对生成式人工智能信任的关键因素及其相互关系。研究发现,外部环境感知、文化情境感知、态度感知与行为控制感知四个核心维度共同塑造了个体的生成式人工智能信任态度。研究为生成式人工智能技术的健康发展、政策制定、企业战略引导及公众接受度的提升,提供了实证基础和理论支持。

基于路网仿射模型的地面编队目标跟踪算法

针对地面多目标跟踪命题,文章首先给出编队目标定义,总结并比较现有编队目标的跟踪方法,在此基础上考虑地面编队目标在路网上编队慢速行进的特点,建立地面编队目标仿射模型,并采用非线性滤波算法对编队整体平移、旋转和缩放行为进行跟踪,从而实现对编队目标的状态估计,进而得到编队目标航迹情报。经数学仿真和实验验证,所提算法具备有效性。

Research on ground fissure origins and mechanisms in Hebei Plain,P.R.China

Ground fissure hazards frequently emerge in Hebei Plain, which damage roads, dams, buildings and farmland. The paper reviews and analyses current state of knowledge and research into ground fissure and geological environment in Hebei Plain. It is shown that the level of research and investigation is in some aspects insufficient. Knowledge is lacking in the use of corresponding geological concept models for specific ground fissures, three-dimensional numerical simulations of ground fissures caused by pumping through soil with pre-existing fractures, numerical simulations of ground fissures caused by dislocation in intersection faults, and the failure criterion and the constitutive relationship of rock and soil. Furthermore, we put forward geological concept models for ground fissure formation following the dislocation of a buried intersection fault, over-exploitation of groundwater and its compound origin mechanisms in order to provide scientific evidence for the quantitative analysis.

δ18O,δD and d-excess signatures of ground ice in permafrost in the Beiluhe Basin on the Qinghai-Tibet Plateau,China

In this paper, stable isotope （δ18O, δD） investigations were completed in ground ice from a deep borehole in the Beiluhe Basin on northern Qinghai-Tibet Plateau to unravel the isotopic variations of ground ice and their possible source water. The δ18O and δD of ground ice show distinctive characteristics compared with precipitation and surface water. The near-surface ground ice is highly enriched in heavier isotopes （δ18O and δD）, which were gradually depleted from top to bottom along the profile. It is suggestive of different origin and ice formation process. According to isotopic variations, the ice profile was divided into three sections： the near-surface ground ice at 2.5 m is frozen by the active-layer water which suffered evaporation. It is possible that ground ice between 3 and 4.2 m is recharged by the infiltration of snowmelt. From 5 to 6 m, the ground ice show complex origin and formation processes. Isotopic variations from 6 to 11.1 m and 20.55 m indicate different replenishment water. The calculated slope of freezing line （S=6.4） is larger than the experimental value （5.76）, and is suggestive of complex origin and formation process of ground ice.