Assessment of first-order-moment-based sample reconstruction method for design flood estimation in changing environment

Estimating the design flood under nonstationary conditions is challenging. In this study, a sample reconstruction approach was developed to transform a nonstationary series into a stationary one in a future time window (FTW). In this approach, the first-order moment (EFTW) of an extreme flood series in the FTW was used, and two possible methods of estimating EFTW values in terms of point values and confidence intervals were developed. Three schemes were proposed to analyze the uncertainty of design flood estimation in terms of sample representativeness, uncertainty from EFTW estimation, and both factors, respectively. To investigate the performance of the sample reconstruction approach, synthesis experiments were designed based on the annual peak series of the Little Sugar Creek in the United States. The results showed that the sample reconstruction approach performed well when the high-order moment of the series did not change significantly in the specified FTW. Otherwise, its performance deteriorated. In addition, the uncertainty of design flood estimation caused by sample representativeness was greater than that caused by EFTW estimation.

Point cloud-based environment reconstruction and ray tracing simulations for railway tunnel channels

Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing system performance.Ray tracing is an effective method to investigate propagation characteristics in a complex environment,and how to quickly and accurately obtain environmental information needs to be solved.This paper presents dynamic environment reconstruction and ray tracing simulation in railway tunnel environment based on Simultaneous Localization and Mapping(SLAM)algorithm and Poisson reconstruction algorithm.Accurate channel parameters are obtained and analyzed based on ray tracing simulation.Both straight and curved tunnels are considered and investigated,and the results show the channel characteristics in complex railway tunnel environments.

A Reconstruction and Discussion of the Effect of Diagenetic Environment on Hydrocarbon Generation Based on Diagenetic Mineral Assemblage in Mudstone

Inorganic minerals in mudstone are composed of clay minerals,carbonate and detrital minerals.Detrital minerals(such as quartz and feldspar)are mainly original deposit.However,clay minerals(kaolinite,illite,and chlorite)and carbonate(calcite and dolomite)are mostly diagenetic minerals.Furthermore,conversion of the four kinds of clay minerals are common.The formation of clay minerals and carbonate is controlled by temperature,pressure,p H,Eh and type of cations during diagenesis.Therefore mineral assemblage can indicate the characteristics and change of diagenetic environment.In addition to inorganic minerals,there are also organic matter of different sources and chemical properties in mudstone.Traditionally,it is considered that evolution of organic matter is controlled by thermal effect.Now studies show that inorganic and organic matter can interact with each other and form clay-organic complexes.This suggest that attention should be paid to the influence of diagenetic mineral assemblage and diagenetic environment on the evolution of organic matter* Samples of mudstone from 1500-4500m of the Palaeogene in the Dongying Depression,China,were collected to investigate the changes of mudstone diagenetic environment.XRD,thin section and SEM were used to detect diagenetic minerals and assemblage characteristics.Results showed that content of detrital minerals,which are floating in mud matrix or preserved as silt laminae,is basically unchanged from shallow to deep strata.Clay minerals which are gathered as argillaceous matrix or preserved as argillaceous laminae have growth and decline relation to carbonate which mainly appear as micropoikilitic ferriferous calcite and ferriferous dolomite.All these characteristics indicate that detrital minerals are exogenetic,whereas carbonate is diagenetic minerals.Based on the SEM analysis of the clay minerals,it was found that smectite present honeycomb and reticulate structure,while illite present filiform and schistose structure and there are growth and decline relationship between them.Nevertheless,hexagonal tabular and stratified kaolinite has the highest content from 2400m to3300m.Rosette and stratified chlorite shows increase trend when the burial depth is deeper than 3300m.These characteristics indicated that clay minerals are diagenetic minerals and there are conversions among the four types.Therefore form shallow to deep,three diagenetic mineral assemblage zones can be divided based on the characteristics of carbonate and clay minerals in mudstone.Namely,smectite+illite/smectite zone in the depth of 2000-2500m;kaolinite+illite/smectite zone in the depth of 2500-3300m and illite+chlorite+carbonate zone below 3300m.Previous studies showed that kaolinite is stable under acidic conditions,while other clay minerals and carbonate are stable under alkaline conditions.Hence according to mineral assemblages feature,it was inferred that diagenetic environment of mudstonehasundergonethechangeof alkaline-acid-alkaline.For the organic matter with different chemical properties in mudstone,the hydrocarbon generation will be different in the acidic and alkaline diagenetic environment even if the conditions of temperature and pressure are the same.Therefore,for hydrocarbon generation we should not only focus on thermal effect,but also pay more attention to the differences of diagenetic environment which have great significance for the understanding of hydrocarbon generation,hydrocarbon expulsion and reservoir formation in mudstone.

Numerical analysis on mechanical difference of sandstone under in-situ stress,pore pressure preserved environment at depth

Deep in-situ rock mechanics considers the influence of the in-situ environment on mechanical properties,differentiating it from traditional rock mechanics.To investigate the effect of in-situ stress,pore pressure preserved environment on the mechanical difference of sandstone,four tests are numerically modeled by COMSOL:conventional triaxial test,conventional pore pressure test,in-situ stress restoration and reconstruction test,and in-situ pore pressure-preserved test(not yet realized in the laboratory).The in-situ stress restoration parameter is introduced to characterize the recovery effect of in-situ stress on elastic modulus and heterogeneous distribution of sandstone at different depths.A random function and nonuniform pore pressure coefficient are employed to describe the non-uniform distribution of pore pressure in the in-situ environment.Numerical results are compared with existing experimental data to validate the models and calibrate the numerical parameters.By extracting mechanical parameters from numerical cores,the stress-strain curves of the four tests under different depths,in-situ stress and pore pressure are compared.The influence of non-uniform pore pressure coefficient and depth on the peak strength of sandstone is analyzed.The results show a strong linear relationship between the in-situ stress restoration parameter and depth,effectively characterizing the enhanced effect of stress restoration and reconstruction methods on the elastic modulus of conventional cores at different depths.The in-situ pore pressurepreserved test exhibits lower peak stress and peak strain compared to the other three tests,and sandstone subjected to non-uniform pore pressure is more prone to plastic damage and failure.Moreover,the influence of non-uniform pore pressure on peak strength gradually diminished with increasing depth.

Stress field evolution law of mining environment reconstructing structure with change of filling height

For improving global stability of mining environment reconstructing structure,the stress field evolution law of the structure with the filling height change of low-grade backfill was studied by ADINA finite element analysis code.Three kinds of filling schemes were designed and calculated,in which the filling heights were 2,4,and 7 m,separately.The results show that there are some rules in the stress field with the increase of the filling height as follows:(1) the maximum value of tension stress of the roof decreases gradually,and stress conditions are improved gradually;(2) the tension stress status in the vertical pillar is transformed into the compressive stress status,and the carrying capacity is improved gradually;however,when the filling height is beyond 2.8 m,the carrying capacity of the vertical pillar grows very slowly,so,there is little significance to continue to fill the low-grade backfill;(3) the bottom pillar suffers the squeezing action from the vertical pillars at first and then the gravity action of the low-grade backfill,and the maximum value of tension stress of the bottom pillar firstly increases and then decreases.Considering the economic factor,security and other factors,the low-grade backfill has the most reasonable height(2.8 m) in the scope of all filling height.

Reconstruction of broken Si–O–Si bonds in iron ore tailings (IOTs) in concrete

This paper reports a study on the reconstruction of broken Si O Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The dif- ferences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and ener- gy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/Si atom ratios in the ITZs of IOTs con- crete samples are lower than those of limestone concrete;the diffraction peak of the calcium silicate phase at 2θ = 29.5°, as well as the bands of Si O bonds shifting to lower wavenumbers, indicates reconstruction of the broken Si-O-Si bonds on the surfaces of IOTs with Ca(OH)2.

营造新型阅读环境:图书馆空间再造反思

图书馆空间服务理论包括图书馆作为空间理论、第三空间理论和空间再造理论。空间再造理论推动图书馆新型空间建设,但许多新型空间脱离了图书馆阅读服务的目标,图书馆人需要运用新的阅读环境营造理论与约束空间再造理论。营造新型阅读环境的主要目标包括:营造保障与服务阅读的环境,营造引导与推广阅读的环境,营造促进与激励阅读的环境。

基于CVM的城市河道改造生态环境价值评估

从城市河道改造的生态环境价值评估角度,分析了条件价值评估法(CVM)在城市河道改造生态环境价值评估中的应用原理和依据,构建了基于CVM的城市河道改造生态环境价值评估模型,并以上海市黄浦江加高堤防替代建闸方案为例对黄浦江河道改造的生态环境价值进行了评估。结果表明:期望均值法和三相定价法计算得到的总支付意愿分别为120.6亿元/a和118.5亿元/a,总受偿意愿为130.8亿元/a和151.2亿元/a,总受偿意愿与总支付意愿的比值大于1;仅从生态环境价值方面看,相对于加高堤防方案,民众更希望政府投资建闸。

西南联大教师兼职研究

在时空不稳定的战争时期,西南联合大学的教学与研究资源受到限制,大后方物价的飞涨导致教师生活难以为继,联大教师相继兼职。这种兼职产生了多方面影响:在一定程度上,主业时间的压缩不可避免地影响了教学工作;学者的社会参与和市场活动改变了其生活样态和思想观念,推动了近代大学价值取向的变迁,使大学的社会服务功能进一步凸显,大学的学术体制在教师的流动中也有所调适;文化资源的流入与再生,则带动了西南地区政治、经济和文化的发展。

Large-scale spatial data visualization method based on augmented reality

Background A task assigned to space exploration satellites involves detecting the physical environment within a certain space.However,space detection data are complex and abstract.These data are not conducive for researchers'visual perceptions of the evolution and interaction of events in the space environment.Methods A time-series dynamic data sampling method for large-scale space was proposed for sample detection data in space and time,and the corresponding relationships between data location features and other attribute features were established.A tone-mapping method based on statistical histogram equalization was proposed and applied to the final attribute feature data.The visualization process is optimized for rendering by merging materials,reducing the number of patches,and performing other operations.Results The results of sampling,feature extraction,and uniform visualization of the detection data of complex types,long duration spans,and uneven spatial distributions were obtained.The real-time visualization of large-scale spatial structures using augmented reality devices,particularly low-performance devices,was also investigated.Conclusions The proposed visualization system can reconstruct the three-dimensional structure of a large-scale space,express the structure and changes in the spatial environment using augmented reality,and assist in intuitively discovering spatial environmental events and evolutionary rules.

Analysis on Typical Spatio-temporal Characteristics of Open-cast Mining and Its Countermeasures

In order to deal with the special spatio-temporal environmental changes encountered in the process of open-cast mining,taking Huolinhe No.1 Open-cast Mine as the research object,this paper studied its typical problems in river reconstruction and cultural relics protection.The study focused on eight key core aspects,including the design optimization of the spatial layout of the mining area,the accurate estimation of the mineral resources reserves,the scientific theoretical demonstration of the mining scale,the fine analysis and calculation of the stripping ratio,the comprehensive consideration of the transport distance and efficiency,the accurate judgment of the best time for the implementation of the transformation,the analysis and evaluation of the slope stability,and the overall planning of the production system.The results show that the extracted problem-solving strategies and scheme system for special mining conditions can not only provide specific and practical guidance for Huolinhe No.1 Open-cast Mine,but also serve as a valuable reference and practical reference for other open-cast mine enterprises facing similar challenges.

大气防疫风环境模拟下探究传统街巷尺度对风环境的影响——以赣州市姚衙前街区为例

后疫情时代疫情防控进入常态化阶段,但是一些具有历史文化的“传统街区”,存在建筑布局紧凑、人口密集等共性问题,在防疫的通风需求方面存在较大隐患。为改善传统历史街区的风环境质量,有效抑制病毒传播,本研究以赣州市姚衙前历史街区为例,基于CFD技术运用斯维尔Vent对赣州市姚衙门前历史街巷进行大气防疫风环境模拟,分析街巷的高度、宽度、长度与地面粗糙度四要素对风环境的影响程度。根据模拟结果得出其对风速影响的权重排序为:街巷高度>宽度>长度,且街巷尺度的宽度为2~4m,高度为3~6m,长度为40~80m,地面粗糙度在0.5~0.75区间中,街巷内风速的影响最大。希望在后期传统历史街巷防疫风环境的改造时,采用某些措施能优化街巷通风能力以达到抑制病毒传播的要求。

关系再造:基层社会的个体动员实践及内在逻辑——基于浙江省嘉兴市秦村的分析

作为一种联结机制,关系在基层社会治理实践中得到了相当广泛的应用。伴随着基层社会治理基础和治理结构的变化,村干部通过个体之间的熟人关系来协调公共事务的空间逐渐缩小。为此,建立在行政任务之上的工作关系、以基层党组织为基础的政治关系、以生活需求为载体的邻里关系和以村民小组为基础的竞争关系等新的关系类型,成为动员村民参与社会治理的重要抓手。不同类型的关系,既体现了治理主体的需求特性,也体现了治理主体之间的依赖性和交换性,维持着乡村社会的基本秩序。

多角度弱纹理文物三维扫描测量方法

古文物的数字化重建是考古发掘的重要分析手段,但弱纹理特征的文物结构很难准确配准,从而引起较大的三维重建误差。针对该问题,提出基于互补格雷码-相移法的三维重建方法,并通过转台辅助完成多角度点云配准。首先,建立双目-转台位姿转换模型,完成系统标定;其次,在扫描过程中使用互补格雷码-相移法获得高质量的相位信息,通过极线校正和立体匹配得到单片点云数据;最后,采用精密转台的多角度拼接方法实现各个方向的点云图像组合,构建完整的文物三维点云图像。为了验证所提方法的有效性,搭建了双目结构光三维重建系统搭配高精度转台实验平台,实验结果表明:所提算法的误差低于0.11 mm,深度相机方法的误差为6.96 mm,比所提方法误差大63.27倍,证明结构光三维重建系统对弱纹理特征物体重建具有优势,同时转台的应用也实现了对均匀对称物体的多角度三维重建。

Ecotect热环境模拟下老旧教学楼围护结构节能改造研究

迫切解决建筑领域“双碳”问题已成为缓解能源危机和环境问题的重要环节。高校校园建筑具有存量大、种类多的特点,且使用能耗大、舒适性低。考虑到使用环境的情况,对高校内老旧建筑的围护结构进行改造是降低能耗的有效做法。采用ECOTECT建筑能耗分析软件,对武汉市某高校第二教学楼的围护结构节能改造方案进行能耗、得热情况和热环境的分析。结果表明,对建筑围护结构的节能改造可以有效的降低能耗以及提高建筑热舒适度。从围护结构改造的角度拟定优化方案,为老旧建筑节能改造提供参考。

贸易环境不确定性对新能源企业成本的影响

受贸易保护主义及地缘政治等因素影响,全球产业链供应链格局持续动荡,本文从外部环境不确定性对新能源企业成本的影响入手,研究发现以下问题:各类贸易壁垒显著增加企业制度交易成本、规则话语权缺失成为产业链供应链重塑的痛点、新能源产业发展的相关体制机制不健全、新能源产业发展政策红利存在减损,并基于此提出看法和建议:应系统应对新能源产业发展贸易壁垒、重视新能源产业规则和制度开放、完善新能源产业发展的体制机制、稳定新能源企业发展的政策预期。

湖北省十堰市历史遗留废弃矿山现状及生态修复工程研究

目的:查明十堰市相对集中连片的历史遗留废弃矿山废弃地分布,分析其对矿区及其周边地形地貌景观、生态功能、水资源水生态、土地资源及矿区人民的生命财产安全的影响。方法:以自然资源部历史遗留废弃矿山管理库数据为基础,充分考虑流域分布与地理单元特性,运用资料收集、实地核查等调查方法。结果:研究区存在矿山地质环境破坏严重、生态功能退化、水土流失严重、水源涵养能力下降等突出问题,因此针对存在的问题,提出了地质灾害隐患治理、地形地貌重塑、土壤重构与植被重建、废弃土地复垦利用、生态修复配套提升、生态环境监测6种工程治理措施。意义:为同类型废弃矿山生态修复提供一定的实践依据。

徽州传统村落文化空间现代性重构策略探究——以祁门文堂村为例

徽州传统建筑是“徽文化”重要的物质空间载体,传承弘扬传统村落文化空间对于增强文化自信心、认同感和归属感具有重要意义。文章以国家级传统村落祁门文堂村为研究对象,通过文献搜集和现场调研,梳理挖掘文堂村文化空间构成要素,针对当前村落文化空间传承发展的困境,提出激活点状文化空间、重塑线状文化空间和统筹面状文化空间的重构策略,探索徽州传统村落文化空间传承与可持续发展的新路径。

Formation,evolution,reconstruction of black shales and their influence on shale oil and gas resource

Black shales are important products of material cycling and energy exchange among the lithosphere,atmosphere,hydrosphere,and biosphere.They are widely distributed throughout geological history and provide essential energy and mineral resources for the development of human society.They also record the evolution process of the earth and improve the understanding of the earth.This review focuses on the diagenesis and formation mechanisms of black shales sedimentation,composition,evolution,and reconstruction,which have had a significant impact on the formation and enrichment of shale oil and gas.In terms of sedimentary environment,black shales can be classified into three types:Marine,terrestrial,and marine-terrestrial transitional facies.The formation processes include mechanisms such as eolian input,hypopycnal flow,gravity-driven and offshore bottom currents.From a geological perspective,the formation of black shales is often closely related to global or regional major geological events.The enrichment of organic matter is generally the result of the interaction and coupling of several factors such as primary productivity,water redox condition,and sedimentation rate.In terms of evolution,black shales have undergone diagenetic evolution of inorganic minerals,thermal evolution of organic matter and hydrocarbon generation,interactions between organic matter and inorganic minerals,and pore evolution.In terms of reconstruction,the effects of fold deformation,uplift and erosion,and fracturing have changed the stress state of black shale reservoirs,thereby having a significant impact on the pore structure.Fluid activity promotes the formation of veins,and have changed the material composition,stress structure,and reservoir properties of black shales.Regarding resource effects,the deposition of black shales is fundamental for shale oil and gas resources,the evolution of black shales promotes the shale oil and gas formation and storage,and the reconstruction of black shales would have caused the heterogeneous distribution of oil and gas in shales.Exploring the formation mechanisms and interactions of black shales at different scales is a key to in-depth research on shale formation and evolution,as well as the key to revealing the mechanism controlling shale oil and gas accumulation.The present records can reveal how these processes worked in geological history,and improve our understanding of the coupling mechanisms among regional geological events,black shales evolution,and shale oil and gas formation and enrichment.

面向6G无线环境可预测的感知重构、语义表征及应用

面对6G通信多样复杂的应用场景,精确低复杂的环境信息和信道模型是实现6G智简传输和组网的基础。面向6G无线环境可预测,对无线环境的感知重构、语义表征与应用展开研究,分析了现有的环境感知技术与重构算法,并对无线环境可预测的语义表征方法进行总结。围绕目前存在的信道建模与预测难题,介绍了信道在线预测的6G网络设计与感知重构平台。相关实验验证了该平台的可行性和准确性。认为未来无线环境可预测的关键是提高无线环境感知精度,提升无线环境语义的可解释性,建立一个面向6G信道的通用性系统模型。