易自燃厚煤层综采工作面CO溯源数值分析

甘肃某矿厚煤层2804综放工作面,回采期间的上隅角CO浓度长期保持150×10^(-6)左右,严重威胁井下人员安全。实验揭示了不同温度和O_(2)浓度下CO生成规律,建立了采空区CO生成运移的热-固-流-化多场耦合模型,定量分析了地温、工作面风量及回采速度对采空区CO生成-运移规律的影响。结果表明,当温度超过40℃时,煤的氧化反应速率开始增加,且随O_(2)浓度增大,煤的氧化反应越剧烈,生成的CO越多;回采过程中工作面上隅角CO浓度呈现递增趋势,生成速率先增大后减小,且随着地温、风量增大而增大;综合分析认为2804工作面上隅角CO主要来源于采空区内部浮煤氧化。

Estimation of the anisotropy of hydraulic conductivity through 3D fracture networks using the directional geological entropy

With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different directions.Compared with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture networks.According to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip angle.As a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.

浅埋近煤层群采动“三区”漏风裂隙场时空演化规律数值模拟

浅埋近煤层群采动下,地面采空区工作面“三区”之间易形成连通的漏气通道引发工作面低氧和采空区煤自燃,如何厘清采动效应下浅埋煤层群“三区”漏气通道的时空分布演化规律是有效防控煤自燃和低氧的关键。以陕煤柠条塔煤矿S1232工作面为研究背景,采用理论与数值模拟相结合的方法,研究了单一煤层、复合煤层重复开采下覆岩破坏特征,分析了煤层间距与采厚对裂隙二次发育的影响规律。结果表明:浅埋近煤层群开采下上覆岩层裂隙仅存在垮落带与裂缝带,主关键层破断后裂缝带快速发育至地表,关键层周期破断控制地表裂隙周期生成与下沉;上煤层裂隙密度发育由原始阶段先后经历快速增长、稳定和二次增长3个阶段;随采厚增大,各区间裂隙密度增大,大裂隙发育更充分,裂隙宽度整体增大;随煤层间距增大,小于0.2 m的裂隙宽度随采厚增大,且增加的速度逐渐加快,大于0.2 m的裂隙宽度随采厚增大,但增加速度逐渐变缓;采厚相同时,裂隙宽度大于0.2 m的裂隙密度随着煤层间距的增大逐渐减小。

Failure behavior and strength model of blocky rock mass with and without rockbolts

To better understand the failure behaviours and strength of bolt-reinforced blocky rocks,large scale extensive laboratory experiments are carried out on blocky rock-like specimens with and without rockbolt reinforcement.The results show that both shear failure and tensile failure along joint surfaces are observed but the shear failure is a main controlling factor for the peak strength of the rock mass with and without rockbolts.The rockbolts are necked and shear deformation simultaneously happens in bolt reinforced rock specimens.As the joint dip angle increases,the joint shear failure becomes more dominant.The number of rockbolts has a significant impact on the peak strain and uniaxial compressive strength(UCS),but little influence on the deformation modulus of the rock mass.Using the Winkler beam model to represent the rockbolt behaviours,an analytical model for the prediction of the strength of boltreinforced blocky rocks is proposed.Good agreement between the UCS values predicted by proposed model and obtained from experiments suggest an encouraging performance of the proposed model.In addition,the performance of the proposed model is further assessed using published results in the literature,indicating the proposed model can be used effectively in the prediction of UCS of bolt-reinforced blocky rocks.

水电站闸门水力振动检测与应用

深入探讨了水电站闸门水力振动的检测与应用,通过闸机事故分析,明确了闸门水力振动对水利设施安全构成的潜在威胁,从而强调了实施有效检测技术的必要性。分析了水闸工程运行管理与维护的重要性,以及在水利工程中闸门水力振动存在的关键问题。详细介绍了闸门水力振动检测技术的应用,包括物理模型试验和具体的检测技术实施步骤,旨在通过科学的方法准确评估闸门的振动情况。针对闸门水力振动的防治措施,涵盖了结构设计优化、材料选择与改进,以及加强运营管理等多个方面,为水电站闸门水力振动的检测与应用提供了全面的分析和实用的参考,有助于提升水利设施的安全性和运行效率。

Algorithmic approach to discrete fracture network flow modeling in consideration of realistic connections in large-scale fracture networks

Analyzing rock mass seepage using the discrete fracture network(DFN)flow model poses challenges when dealing with complex fracture networks.This paper presents a novel DFN flow model that incorporates the actual connections of large-scale fractures.Notably,this model efficiently manages over 20,000 fractures without necessitating adjustments to the DFN geometry.All geometric analyses,such as identifying connected fractures,dividing the two-dimensional domain into closed loops,triangulating arbitrary loops,and refining triangular elements,are fully automated.The analysis processes are comprehensively introduced,and core algorithms,along with their pseudo-codes,are outlined and explained to assist readers in their programming endeavors.The accuracy of geometric analyses is validated through topological graphs representing the connection relationships between fractures.In practical application,the proposed model is employed to assess the water-sealing effectiveness of an underground storage cavern project.The analysis results indicate that the existing design scheme can effectively prevent the stored oil from leaking in the presence of both dense and sparse fractures.Furthermore,following extensive modification and optimization,the scale and precision of model computation suggest that the proposed model and developed codes can meet the requirements of engineering applications.

Preparation and Analysis of Carbon Fiber-Silicon Carbide Thermally Conductive Asphalt Concrete

An experimental investigation into the thermal conductivity of CF-SiC two-phase composite asphalt concrete is presented.The main objective of this study was to verify the possibility of using SiC powder instead of mineral powder as the thermal conductive filler to prepare a new type of asphalt concrete and improve the efficiency of electrothermal snow and ice melting systems accordingly.The thermal conductivity of asphalt concrete prepared with different thermally conductive fillers was tested by a transient plane source method,and the related performances were measured.Then the temperature rise rate and surface temperature were studied through field heating tests.Finally,the actual ice melting efficiency of the thermally conductive asphalt concrete was evaluated using an effective electrothermal system.As shown by the experimental results,the composite made of SiC powder and carbon fiber has a high thermal conductivity.When SiC replaces mineral powder,the thermal conductivity of the asphalt mixture increases first and then decreases with the increase of carbon fiber content.In the present study,in particular,the thermal conductivity attained a peak when the carbon fiber content was 0.2%of the aggregate mass.

Fluorescent,multifunctional anti-counterfeiting,fast response electrophoretic display based on TiO_(2)/CsPbBr_(3)composite particles

Traditional optical anti-counterfeiting(AC)is achieved by static printed images,which makes them susceptible to lower levels of security and easier replication.Therefore,it is essential to develop AC device with dynamic modulation for higher security.Electrophoretic display(EPD)has the advantages of low power consumption,high ambient contrast ratio,and capability of showing dynamic images which is suitable for dynamic AC applications.Herein,we prepared a dynamical AC device based on a fluorescent EPD,and achieving the image switch between black,white,and green fluorescence states under the dual-mode driving(electronic field and Uv light).We loaded perovskite quantum dots(CsPbBr3)onto the TiO_(2) particles and further prepared fluorescent electrophoretic particles TiO_(2)/CsPbBr_(3)-3-PLMA(TiO/CPB-3)by grafting and polymerizing method.In addition,We fabricated the AC devices based on the fluorescent EPD,which exhibits the multifunctional AC,where the fluorescent EPD has a fast response time of 350 ms,a high contrast ratio of 17,and bright green fluorescence.This prototype demonstrates a new way for future dynamic AC and identification.

Unraveling the mechanism of malancao in treating ulcerative colitis:A multi-omics approach

BACKGROUND Malancao(MLC)is a traditional Chinese medicine with a long history of utilization in treating ulcerative colitis(UC).Nevertheless,the precise molecular mechanisms underlying its efficacy remain elusive.This study leveraged ultrahigh-performance liquid chromatography coupled with exactive mass spectrometry(UHPLC-QE-MS),network pharmacology,molecular docking(MD),and gene microarray analysis to discern the bioactive constituents and the potential mechanism of action of MLC in UC management.AIM To determine the ingredients related to MLC for treatment of UC using multiple databases to obtain potential targets for fishing.METHODS This research employs UHPLC-QE-MS for the identification of bioactive compounds present in MLC plant samples.Furthermore,the study integrates the identified MLC compound-related targets with publicly available databases to elucidate common drug disease targets.Additionally,the R programming language is utilized to predict the central targets and molecular pathways that MLC may impact in the treatment of UC.Finally,MD are conducted using AutoDock Vina software to assess the affinity of bioactive components to the main targets and confirm their therapeutic potential.RESULTS Firstly,through a comprehensive analysis of UHPLC-QE-MS data and public database resources,we identified 146 drug-disease cross targets related to 11 bioactive components.The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis highlighted that common disease drug targets are primarily involved in oxidative stress management,lipid metabolism,atherosclerosis,and other processes.They also affect AGE-RAGE and apoptosis signaling pathways.Secondly,by analyzing the differences in diseases,we identified key research targets.These core targets are related to 11 active substances,including active ingredients such as quercetin and luteolin.Finally,MD analysis revealed the stability of compound-protein binding,particularly between JUNLuteolin,JUN-Quercetin,HSP90AA1-Wogonin,and HSP90AA1-Rhein.Therefore,this suggests that MLC may help alleviate intestinal inflammation in UC,restore abnormal lipid accumulation,and regulate the expression levels of core proteins in the intestine.CONCLUSION The utilization of MLC has demonstrated notable therapeutic efficacy in the management of UC by means of the compound target interaction pathway.The amalgamation of botanical resources,metabolomics,natural products,MD,and gene chip technology presents a propitious methodology for investigating therapeutic targets of herbal medicines and discerning novel bioactive constituents.

Enhanced ortho-selective t–butylation of phenol over sulfonic acid functionalized mesopore MTW zeolites

Novel organo-inorganic hybrid materials(MTW-x-SO_(3)H) have been fabricated by immobilizing 3-mercap topropyltriethoxysilane onto mesopore MTW zeolites, which is treated via a simple oxidation process with hydrogen peroxide as the oxidant to transform sulfhydryl group into sulfonic acid group. The organic sulfhydryl groups are covalently bonded to the external surface of MTW zeolites through the condensation between siloxane arising from organic fragments with silanol groups on the surface of MTW zeolites, the hybrids contain sulfonic acid group within the external surface of MTW zeolites and an opened mesoporous system in the matrix of MTW zeolites, which provide enough accessible Brùnsted acid sites for the alkylation between phenol with tert-butyl alcohol. Through this methodology it's possible to prepare multifunctional materials where the plenty of mesopores are benefit for the introduction of larger numbers of sulfonic acid groups that contributes to activity during reactions, resulting in high activity(>55%) of MTW-4-SO_(3)H and desired selectivity(>56%) of 2-TBP(2-tert-butyl phenol) in the alkylation between phenol with tert-butyl alcohol.

Enhancing hydrophobicity via core-shell metal organic frameworks for high-humidity flue gas CO_(2) capture

Developing metal-organic framework(MOF)materials with the moisture-resistant feature is highly desirable for CO_(2)capture from highly humid flue gas.In this work,a new core-shell MOF@MOF composite using Mg-MOF-74 with high CO_(2)capture capacity as a functional core and hydrophobic zeolitic imidazolate framework-8(ZIF-8)as a protective shell is fabricated by the epitaxial growth method.Experimental results show that the CO_(2)adsorption performance of the core-shell structured Mg-MOF-74@ZIF-8 composites from water-containing flue gas is enhanced along with their improved hydrophobicity.The dynamic breakthrough results show that the Mg-MOF-74@ZIF-8 with three assembled layers(Mg-MOF-74@ZIF-8-3)can capture 3.56 mmol-g^(-1)CO_(2)from wet CO_(2)/N_(2)(VCO_(2):V_(N_(2))=15:85)mixtures,which outperforms Mg-MOF-74(0.37 mmol·g^(-1))and most of the reported physisorbents.

国家斑马鱼资源中心的资源、技术和服务建设

随着我国斑马鱼研究群体的日益壮大,对各类斑马鱼研究资源和技术的需求日益增加,国家斑马鱼资源中心(China Zebrafish Resource Center,CZRC,网址:http://zfish.cn)于2012年在中国科学院水生生物研究所成立。目前,CZRC已发展成为国内规模最大的单体斑马鱼养殖系统,建成包含1200多个斑马鱼品系和10 000余份冻存精子的斑马鱼资源保藏库,其中有超过200个突变和转基因品系是由CZRC自主创制。在此基础上,CZRC建立了安全规范的斑马鱼养殖和健康平台、高效的基因操作平台和稳定高效的精子冻存平台。CZRC致力于为国内外从事斑马鱼研究的科研人员提供各类服务,包括提供斑马鱼品系等资源服务、转基因和基因敲除等技术服务、养殖和健康等咨询服务,以及技术培训和学术会议服务等。经过5年的建设,CZRC已成为国际学术界公认的全球三大斑马鱼资源库之一。

综掘工作面不同截割方式下的最佳风场调控规则

针对目前综掘工作面局部通风方式下,出风口风流状态不能根据实际通风需求进行动态变化,造成巷道内粉尘与瓦斯聚集严重问题,通过最佳风场调控规则分析,以求有效降低粉尘质量浓度和瓦斯体积分数。采用正交试验及流场模拟实验方法分析不同截割方式下风流参数变化对风速、瓦斯及粉尘场分布影响规律,获取大量样本数据,建立风场调控参数与风速、瓦斯及粉尘质量浓度关联关系的初始化决策信息系统,并对其进行K-means算法离散化合并规约处理,建立离散化决策信息系统。基于粒计算和Matlab软件编写了风场调控规则获取的智能算法和参数化程序。利用风场调控规则获取方法和参数化程序分析并建立了陕西神木柠条塔矿S1212胶运巷道综掘工作面的最佳风场调控规则,并利用自主研制的风流调控装置进行了井下测试验证。结果表明:经使用最佳风场调控规则后,巷道内风速在0.25~4.00 m/s及死角区域瓦斯体积分数低于1%的前提下,出风口距掘进工作面最近距离5 m时,回风侧粉尘质量浓度最高降低43%,司机处粉尘质量浓度最高降低38%;出风口距掘进工作面最远距离10 m时,回风侧粉尘质量浓度最高降低15%,司机处粉尘质量浓度最高降低37%。

综掘面尘源动态变化下粉尘场优化的风流调控研究

针对综掘面风流状态不能实时动态变化及粉尘源位置不断移动导致巷道粉尘聚集严重等问题,设计了风流调控下粉尘场模拟的正交试验方案,采用FLUENT软件模拟分析了尘源动态变化下风流调控参数对粉尘浓度分布影响规律,并运用极差分析法分析了风筒出风口口径、水平偏转角度、垂直偏转角度三个影响因素的显著性,确定了粉尘场优化分布的风流调控方案。对柠条塔矿S1212胶运巷道出风口距迎头5m和10m时的风流调控进行实际测试得出:回风侧行人呼吸带高度平均粉尘浓度分别降低33.4%和34.3%,掘进司机处粉尘浓度分别降低45.3%和40.4%,结果表明,根据实际需求建立出风口风流调控方案,对出风口风流状态进行调控可以优化粉尘场分布,降低粉尘浓度,改善通风环境。

掘进工作面长压短抽通风出风口风流调控参数研究

掘进工作面长压短抽通风方式下出风口风流不能根据掘进过程的实际需求进行动态调控,进而造成风流分布不合理,粉尘聚集严重。现有针对掘进工作面长压短抽通风出风口风流分布及降尘效果的研究都只是单一地分析了风筒出风口参数变化对掘进工作面风流分布及降尘效果的影响,未考虑各参数之间对粉尘场运移分布的交互影响,且对在不同掘进阶段,出风口参数如何综合变化才能达到最佳的通风降尘效果的研究不深入。针对上述问题,以陕西榆林神木柠条塔矿S1204掘进工作面为研究对象,建立了出风口参数可以变化的风流调控有限元模型,模拟分析了风筒出风口参数变化对风流及粉尘浓度运移分布的影响,通过数值分析选取了风筒出风口口径、水平右偏角度和垂直上偏角度作为出风口风流动态调控参数,提取了不同风流调控参数调控后司机位置处及回风侧行人位置处的风速及粉尘浓度数据。通过小生境遗传算法,以司机位置处及回风侧行人位置处的粉尘浓度同时最低为优化目标对提取的风流调控数据进行挖掘分析,获取了S1204掘进工作面出风口距掘进端面最近距离5 m和最远距离10 m时的最佳风流调控参数:在5 m处,出风口口径为1.1~1.2 m,水平右偏角度为10~15°,垂直上偏角度为3~6°;在10 m处,出风口口径为0.8~0.9 m,水平右偏角度为0~5°,垂直上偏角度为0~3°。搭建了1∶5相似模拟的S1204掘进工作面风流智能调控实验测试平台,对最佳风流调控参数进行了测试分析,结果表明:司机位置处的粉尘浓度最高降低了52.3%,回风侧行人位置处的粉尘浓度最高降低了60.6%,验证了最佳风流调控参数的准确性。

水库运用期的设计洪水理论和方法

水利水电工程兴建和气候环境变化,明显改变了河川径流及洪水的时程分配过程,并直接影响下游断面的设计洪水。本文综述讨论水电工程建设期的设计洪水、分期设计洪水、动态设计洪水和受上游水库影响设计洪水的研究进展及存在问题。提出水库运用期的设计洪水的科学问题,研究内容和关键技术,重点介绍最可能地区洪水组成和多变量分析理论和方法,为开展受上游水库运行调蓄影响条件下水库运用期设计洪水研究提供思路和方向。

DMB+,新一代数据传播技术

针对通信网络在公共信息发布时传输效率低、可靠性差等问题,提出DMB+(digital multimedia broadcast plus)数据传播新技术。采用编码正交频分复用(coded orthogonal frequency division multiplexing,COFDM)、终端识别等技术,以无线广播的方式,面向大量终端实时分类传输文字、数据、图片、视频等信息。DMB+具有无线传输、覆盖范围大、施工和维护简单等优点,可以弥补现有通信技术的不足,更适用于终端数量多和人群密集的应用场景,如学校、工矿企业、社区以及智慧城市和公共安全等相关应用。DMB+的时间精准性、数据安全性使其能在保密专用通信、工业控制以及中国制造2025应用中发挥特定的作用。全面介绍DMB+的研究背景、关键技术和应用方案,并对DMB+的产业前景进行了探讨。

连采掘进面压入式通风下最佳风场调控规则研究

针对连采掘进面压入式通风系统不能实时改变风流状态造成风场分布不均、瓦斯及粉尘积聚严重等隐患问题,提出利用风筒出风口风流动态调控来优化风场分布,进而达到高效通风降尘需求。采用流场数值模拟及井下实测手段提取风流调控参数与风速、瓦斯及粉尘质量浓度关联关系的样本数据,利用K-means算法和四段式编码建立风场调控下的瓦斯及粉尘质量浓度信息库,基于小生境遗传算法建立最佳风场调控规则获取方法并开发参数化程序。利用自主研制的风流调控装置在柠条塔S1231面进行最佳风场调控规则井下测试验证和效果分析。结果表明:出风口距迎头最近距离5 m和最远距离10 m时实测值均在调控规则计算值范围内,距迎头5 m时司机处粉尘质量浓度最高降低46%,回风侧粉尘质量浓度最高降低49%;距迎头10 m时司机处粉尘质量浓度最高降低55%,回风侧粉尘质量浓度最高降低52%;验证了调控规则的准确性和有效性,可为连采掘进面的风场动态调控提供理论依据。

城市空间纬度下的优质小学教育资源非均等化机理探寻——以武汉市为例

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