期刊文献+
共找到21,031篇文章
< 1 2 250 >
每页显示 20 50 100
融入混合注意力的低缩放因子SeamCarving篡改检测算法
1
作者 赵洁 常皓婵 武斌 《智能科学与技术学报》 CSCD 2024年第2期244-252,共9页
针对现有的Seam Carving篡改检测算法对于低缩放因子情况存在检测精度不高、鲁棒性不强的问题,提出一种融入混合注意力机制的Seam Carving篡改检测算法。首先,利用BayarConv2D约束卷积对图像进行预处理,充分学习图像的噪声特征,并通过... 针对现有的Seam Carving篡改检测算法对于低缩放因子情况存在检测精度不高、鲁棒性不强的问题,提出一种融入混合注意力机制的Seam Carving篡改检测算法。首先,利用BayarConv2D约束卷积对图像进行预处理,充分学习图像的噪声特征,并通过矩阵乘法与RGB图像进行特征融合;然后,采用ResNet作为骨干网络进行特征学习,引入残差传播和残差反馈机制,凸显Seam Carving的操作痕迹;最后,利用混合注意力机制同时提取相邻位置和通道之间的特征,更好地捕捉全局特征,进而将其输入全连接层进行分类。实验结果表明,在BOSSbase1.01数据集上,当缩放因子为1%和9%时,检测精度分别达到了89.48%和97.94%,优于现有主流方法,同时具有较低的计算复杂度和较好的鲁棒性,能够抵抗JPEG压缩攻击。 展开更多
关键词 混合注意力机制 图像取证 seam Carving检测 低缩放因子
下载PDF
基于动态规划的Seam Carving裁剪算法
2
作者 杨科林 杨斌 +3 位作者 秦崇良 雷荣军 张永超 屈睿涛 《软件工程与应用》 2024年第3期439-445,共7页
随着科技的发展,图像应用和分享越来越普遍。图像尺寸调整在不同设备和屏幕上的显示非常重要。传统的方法只是简单地复制或计算像素值,而不考虑图像内容的重要性。然而,基于动态规划的Seam Carving裁剪算法提出了一种更优化的方法。该... 随着科技的发展,图像应用和分享越来越普遍。图像尺寸调整在不同设备和屏幕上的显示非常重要。传统的方法只是简单地复制或计算像素值,而不考虑图像内容的重要性。然而,基于动态规划的Seam Carving裁剪算法提出了一种更优化的方法。该算法采用多尺度处理,对不同尺度的图像进行Seam Carving操作,并将处理结果整合起来,以实现更全面、更精细的图像调整。 展开更多
关键词 动态规划 多尺度处理 梯度能量函数 seam Carving裁剪算法
下载PDF
Insights into carbon dioxide sequestration into coal seams through coupled gas flow-adsorption-deformation modelling
3
作者 Hywel Thomas Min Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期26-40,共15页
Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration potential.Since the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this... Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration potential.Since the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection period.This paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is considered.The reliability of the proposed adsorption-desorption isotherm is examined via validation tests.It is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore deformation.After injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant drop.Although the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption hysteresis.The unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams. 展开更多
关键词 CO_(2)geological storage Coal seam ADSORPTION Desorption hysteresis
下载PDF
Stability analysis of longwall top-coal caving face in extra-thick coal seams based on an innovative numerical hydraulic support model
4
作者 Jun Guo Wenbo Huang +7 位作者 Guorui Feng Jinwen Bai Lirong Li Zi Wang Luyang Yu Xiaoze Wen Jie Zhang Wenming Feng 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第4期491-505,共15页
The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct ... The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal. 展开更多
关键词 Extremely thick coal seam Fully mechanized top coal caving Support strength Support-surrounding rock interaction
下载PDF
Astronomical influence of the development of Paleogene thin coal seam groups in offshore Lacustrine basins:A case study of the ZhuⅠDepression's Enping Formation located in the northern South China Sea
5
作者 Yan Liu Shengbing Huang +4 位作者 Dongdong Wang Nan Li Yuting Yin Ying Chen Zengxue Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第4期136-150,共15页
The development of the Paleogene coal seams in China's offshore basin areas generally had the characteristics of coal measures with large thicknesses,large numbers of coal seams,thin single coal seams,poor stabili... The development of the Paleogene coal seams in China's offshore basin areas generally had the characteristics of coal measures with large thicknesses,large numbers of coal seams,thin single coal seams,poor stability,scattered vertical distribution,and a wide distribution range.This study selected the Enping Formation of the ZhuⅠDepression in the northern section of the South China Sea as an example to determine the macro-control factors of the development of the Paleogene coal seam groups.An analysis was carried out on the influencing effects and patterns of the astronomical cycles related to the development of the thin coal seam groups in the region.A floating astronomical time scale of the Enping Formation was established,and the sedimentary time limit of the Enping Formation was determined to be approximately 6.15 Ma±.In addition,the cyclostratigraphy analysis results of the natural gamma-ray data of Well XJ in the Enping Formation of the Xijiang Sag revealed that the development of the thin coal seams had probably been affected by short eccentricity and precession factors.The formation process of coal seams was determined to have been affected by high seasonal contrast,precipitation,and insolation.During the periods with high values of short eccentricity,the seasonal contrasts tended to be high.During those periods,fluctuations in the precession controls resulted in periodic volume changes in precipitation and insolation of the region,resulting in the development of thin coal seams.It was also found that the periods with low precession were the most conducive to coal seam development.On that basis,combined with such factors as sedimentary environmental conditions conducive to the development of thin coal seam groups,this study established a theoretical model of the comprehensive influences of short eccentricity and precession on the development and distribution of Paleogene thin coal seam groups in offshore lacustrine basins.The patterns of the Paleogene astronomical periods and paleoclimate evolution,along with the control factors which impacted the development of thin coal seam groups in offshore lacustrine basins,were revealed. 展开更多
关键词 PALEOGENE Pearl(Zhujiang)River Mouth Basin coal seam development astronomical cycles
下载PDF
Research on the mechanism of rockburst induced by mined coal-rock linkage of sharply inclined coal seams
6
作者 Xingping Lai Huicong Xu +4 位作者 Pengfei Shan Qinxin Hu Weixi Ding Shangtong Yang Zhongming Yan 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期929-942,共14页
In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue t... In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue that affects the safe mining of deep,steeply inclined coal seams.In this work,we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data.We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof,explaining the mechanical response behavior of key disaster-prone zones within the deep working face,affected by the dynamics of deep mining.By exploring the spatial correlation inherent in extensive microseismic data,we delineate the“time-space”response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face.The results disclose that(1)the distinctive coal-rock occurrence structure characterized by a“sandwiched rock pillar-B6 roof”constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine,with both elements presenting different degrees of deformation localization with increasing mining depth.(2)As mining depth increases,the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration.The localized deformation of deep,steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions,increasing the energy distribution disparity and stress asymmetry of the“sandwiched rock pillar-B3+6 coal seam-B6 roof”configuration.This makes worse the propensity for frequent dynamic disasters in the working face.(3)The developed high-energy distortion zone“inner-outer”control technology effectively reduces high stress concentration and energy distortion in the surrounding rock.After implementation,the average apparent resistivity in the rock pillar and B6 roof substantially increased by 430%and 300%,respectively,thus guaranteeing the safe and efficient development of steeply inclined coal seams. 展开更多
关键词 steeply inclined coal seam localized deformation mechanism of induced rockburst prevention and control of rockburst
下载PDF
基于SEAMS评估的针对性护理干预在老年高血压患者的血压控制及用药依从性的影响
7
作者 吴秀琴 钱彐晴 龚林 《黑龙江医药科学》 2024年第2期84-85,89,共3页
目的:探讨基于用药自我效能量表(SEAMS)评估的针对性护理对老年高血压的应用效果。方法:纳入2021年1月至2023年8月于上饶市人民医院门诊收治的65例老年高血压患者,根据抛掷法分为SEAMS组(基于SEAMS评估的针对性护理)33例、常规组(一般护... 目的:探讨基于用药自我效能量表(SEAMS)评估的针对性护理对老年高血压的应用效果。方法:纳入2021年1月至2023年8月于上饶市人民医院门诊收治的65例老年高血压患者,根据抛掷法分为SEAMS组(基于SEAMS评估的针对性护理)33例、常规组(一般护理)32例,干预3个月。比较两组血压控制、用药依从性、自我管理能力、健康状况。结果:SEAMS组干预后血压值较常规组低(P<0.05),SEAMS组血压控制率高于常规组(P<0.05),SEAMS组高血压患者服药依从性自我效能量表(MASES-R)评分、SEAMS评分、高血压病人自我管理量表评分、自测健康评定量表评分较常规组高(P<0.05)。结论:对老年高血压患者行基于SEAMS评估的针对性护理干预可控制血压水平,提升用药依从性、自我管理能力,改善健康状况。 展开更多
关键词 seamS 针对性护理 老年高血压
下载PDF
Analysis of the Risk of Water Breakout in the Bottom Plate of High-Intensity Mining of Extra-Thick Coal Seams
8
作者 Shuo Wang Hongdong Kang Xinchen Wang 《Journal of Geoscience and Environment Protection》 2024年第5期81-91,共11页
In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site moni... In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard. 展开更多
关键词 Extra-Thick Coal seam High-Intensity Mining Microseismic Monitoring Water-Surge Hazard Borehole Peeping
下载PDF
GMAS、MMAS-8和SEAMS评估慢性病病人用药依从性效能的比较 被引量:12
9
作者 兰琨熠 张清 沈悦好 《护理研究》 北大核心 2023年第13期2322-2328,共7页
目的:比较普适性药物依从性量表(GMAS)、Morisky服药依从性测量量表(MMAS-8)、合理用药自我效能量表(SEAMS)在慢性病病人中的应用效果,为临床选择有价值的慢性病用药依从性评估工具提供参考。方法:于2021年10月—2022年2月选取在天津市... 目的:比较普适性药物依从性量表(GMAS)、Morisky服药依从性测量量表(MMAS-8)、合理用药自我效能量表(SEAMS)在慢性病病人中的应用效果,为临床选择有价值的慢性病用药依从性评估工具提供参考。方法:于2021年10月—2022年2月选取在天津市3所医疗机构就诊的270例成年慢性病病人为研究对象,采用一般资料调查表、GMAS、MMAS-8、SEAMS进行用药依从性评估,并以MAQ作为效度评价标准,采用受试者工作特征(ROC)曲线、Bayes判别分析、Kappa一致性检验和阳性似然比对3种慢性病用药依从性评估工具进行比较。结果:以MAQ为评价标准,270例病人中用药依从性差者122例(45.2%)。GMAS、MMAS-8、SEAMS评分的ROC曲线下面积(AUC)分别为0.981,0.984,0.917,灵敏度分别为0.987,0.993,0.676,特异度分别为0.926,0.943,0.951,约登指数分别为0.913,0.936,0.627(P<0.001)。GMAS、MMAS-8和SEAMS对评估慢性病病人用药依从性的交叉检验准确率分别为89.6%、97.0%和80.7%,与MAQ评估结果的一致性检验Kappa值分别为0.917,0.940,0.608(P<0.001),阳性似然比分别为13.367,17.303,13.734。结论:3种量表在评估慢性病病人是否存在用药依从性不佳风险时均有较高价值,其中MMAS-8评估慢性病病人用药依从性的效能最高,GMAS量表次之,最后是SEAMS,提示研究人员可根据研究对象个性化特点和研究目的针对性地选择评估工具,有助于准确识别用药依从性不佳的慢性病病人并早期开展干预。 展开更多
关键词 慢性病 用药依从性 普适性药物依从性量表(GMAS) Morisky服药依从性测量量表(MMAS-8) 合理用药自我效能量表(seamS)
下载PDF
Parametric study on the ballistic performance of seamed woven fabrics 被引量:1
10
作者 Hang Li Rui Zhang +2 位作者 Shengnan Min Yi Zhou Jiuxiao Sun 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期173-189,共17页
The ballistic perforation response of composite fabrics made by combining plain weaves with seaming technology is reported and compared with conventional unseamed plain fabrics.The effect of the seaming technique on t... The ballistic perforation response of composite fabrics made by combining plain weaves with seaming technology is reported and compared with conventional unseamed plain fabrics.The effect of the seaming technique on the ballistic resistance of aramid plain fabrics is investigated by varying the seaming process.The ballistic experiment uses 8 mm diameter spherical projectiles to impact different fabric sample targets with velocities of 230 m/s and 400 m/s.The ballistic performance of seamed and unseamed fabrics is characterized by the specific energy absorption(SEA)values of the fabrics.The results show that the seamed fabric has a better energy absorption capacity than the unseamed fabric,e.g.,the SEA of sample 5(seaming lines on every four yarns in a single-ply fabric system)is 135%of sample 1(plain weave without thread seaming).In the single-layer system,the effect of the seaming technique on the energy absorption of the fabric in significant when considering seaming density,seaming orientation,seaming distance,and seaming material on the plain fabric;In addition,it is found that in multi-layer systems,seamed panels(e.g.,sample 7)exhibit better ballistic performance than multi-layer fabrics(e.g.,sample 2),and the specific energy absorption of sample 7 is approximately 156%and 200%of sample 6 and sample 2,respectively.Meanwhile,the energy absorption of the fabric decreases with the increase of impact velocity,which is related to the energy absorption mechanism of the soft fabric system at high impact velocities.The yarn pull-out tests shows that the constraint provided by the seaming thread increases the friction between the fabric-forming yarns.However,when the constraint exceeds a certain level,it is detrimental to the energy absorption of the fabric,which may be due to the overconstraint of yarn mobility. 展开更多
关键词 FABRIC Ballistic performance seaming technology Energy absorption
下载PDF
Movement and deformation characteristics of overlying rock mass in deep coal seam 被引量:1
11
作者 LI Yong ZHENG Jing +4 位作者 WANG Feng-nian HU Chao-wen YANG Fan MA Xin-gen TAO Zhi-gang 《Journal of Mountain Science》 SCIE CSCD 2023年第6期1725-1741,共17页
The 110 mining method is an innovative and useful coal mining technology.It mainly relies on two technologies to improve coal mining rate:Top cutting and pressure relief,Negative Poisson’s ratio anchor cable(NPR anch... The 110 mining method is an innovative and useful coal mining technology.It mainly relies on two technologies to improve coal mining rate:Top cutting and pressure relief,Negative Poisson’s ratio anchor cable(NPR anchor cable)support.This study develops a large-scale physical model test using the speckle monitoring system(DIC),the stress-strain monitoring system,and the infrared thermal imaging system to deeply investigate the roadway deformation and failure law of the 110 mining method,the displacement movement mechanism of the overlying rock mass,and the change law of rock pressure.Results showed that pillarless coal mining utilizing mine pressure and rock fragmentation and expansion characteristics,the use of cut top pressure relief and NPR anchor stress compensation technology in the kilometer level of deep underground coal mining still has a positive effect along the tunnel space.In addition,they can reduce surface subsidence,provide a scientific basis for ecological protection,and develop other kilometer-level deep soft rock high-ground stress underground projects. 展开更多
关键词 Cut seam DISPLACEMENT NPR anchor cable Physical model Numerical simulation
下载PDF
Correction to:Application of long-reach directional drilling boreholes for gas drainage of adjacent seams in coal mines with severe geological conditions
12
作者 Grzegorz Lesniak Daniel J.Brunner +7 位作者 Tomasz Topor Matgorzata Stota-Valim Renata Cicha-Szot Bartomiej Jura Jacek Skiba Arnold Przystolik Ben Lyddall Grzegorz Plonka 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第3期225-225,共1页
Correction:International Journal of Coal Science&Technology(2022)9:88 https:/doi.org/10.1007/s40789-022-00553-6 In this article,the author would like to change the Ethics Declaration as below:EthicsDeclarations Sc... Correction:International Journal of Coal Science&Technology(2022)9:88 https:/doi.org/10.1007/s40789-022-00553-6 In this article,the author would like to change the Ethics Declaration as below:EthicsDeclarations Scientific work published within the framework of an international project DD-MET co-financed by the Research Fund for Coal and Steel(RFCS),(Grant Agreement:847338)and by the Polish Ministry of Science and Higher Education(Contract no.5073/FBWiS/19/2020/2 and 5038/FBWiS/2019/2). 展开更多
关键词 directional FINANCE seam
下载PDF
Ground fissure development regularity and formation mechanism of shallow buried coal seam mining with Karst landform in Jiaozi coal mine: a case study
13
作者 ZHU Heng-zhong 《Journal of Mountain Science》 SCIE CSCD 2023年第10期3101-3120,共20页
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,geogr... 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. 展开更多
关键词 Karst landform Shallow buried coal seam Development regularity Formation mechanism Ground fissure Repeated mining
下载PDF
Geopolymer-based modification of blasting sealing materials and optimization of blasting block size in coal seams of open pit mines
14
作者 Xiaohua Ding Zhongchen Ao +5 位作者 Wei Zhou Hao Qin Zhongao Yang Wen An Xiaoshuang Li Honglin Liu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第12期1551-1562,共12页
This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study f... This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study first focused on optimizing the strength of the sealant material and reducing curing time.This was achieved by regulating the slag doping and sodium silicate solution modulus.The findings demonstrated that increasing slag content and improving the material resulted in an early rise in strength while increasing the modulus of the sodium silicate solution extended the curing time.The slag doping level was fixed at 80 g,and the sodium silicate solution modulus was set at 1.5.To achieve a strength of 3.12 MPa,the water/gel ratio was set at 0.5.The initial setting time was determined to be 33 min,meeting the required field test duration.Secondly,the strength requirements for field implementation were assessed by simulating the action time and force destruction process of the sealing material during blasting using ANSYS/LS-DYNA software.The results indicated that the modified material meets these requirements.Finally,the Shengli Open Pit Coal Mine served as the site for the field test.It was observed that the hole-sealing material’s hydration reaction created a laminated and flocculated gel inside it.This enhanced the density of the modified material.Additionally,the pregelatinized starch,functioning as an organic binder,filled the gaps between the gels,enhancing the cohesion and bonding coefficient of the material.Upon analyzing the post-blasting shooting effect diagram using the Split-Desktop software,it was determined that the utilization of the modified blast hole plugging material resulted in a decrease in the rate of coal fragmentation from 33.2%to 21.1%.This reduction exhibited a minimal error of 1.63%when compared to the field measurement,thereby providing further confirmation of the exceptional plugging capabilities of the modified material.This study significantly contributes to establishing a solid theoretical basis for enhancing the blasting efficiency of open pit mines and,in turn,enhancing their economic advantages. 展开更多
关键词 Open pit coal mine Coal seam blasting Sealing materials Block size optimization Numerical simulation
下载PDF
In-situ gas contents of a multi-section coal seam in Sydney basin for coal and gas outburst management
15
作者 Zhongbei Li Ting Ren +4 位作者 Dennis Black Ming Qiao Itmam Abedin Jessica Juric Mike Wang 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第4期34-46,共13页
The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative... The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative coal seam with multiple sections (A1, A2, and A3) in the Sydney basin, where the CO_(2) composition exceeds 90%. The fast direct desorption method and associated devices were described in detail and employed to measure the in-situ gas components (Q_(1), Q_(2), and Q_(3)) of the coal seam. The results show that in-situ total gas content (Q_(T)) ranges from 9.48 m^(3)/t for the A2 section to 14.80 m^(3)/t for the A3 section, surpassing the Level 2 outburst threshold limit value, thereby necessitating gas drainage measures. Among the gas components, Q_(2) demonstrates the highest contribution to Q_(T), ranging between 55% and 70%. Furthermore, high-pressure isothermal gas sorption experiments were conducted on coal samples from each seam section to explore their gas sorption capacity. The Langmuir model accurately characterizes CO_(2) sorption behavior, with ft coefcients (R^(2)) greater than 0.99. Strong positive correlations are observed between in-situ gas content and Langmuir volume, as well as between residual gas content (Q_(3)) and sorption hysteresis. Notably, the A3 seam section is proved to have a higher outburst propensity due to its higher Q_(1) and Q_(2) gas contents, lower sorption hysteresis, and reduced coal toughness f value. The insights derived from the study can contribute to the development of efective gas management strategies and enhance the safety and efciency of coal mining operations. 展开更多
关键词 In-situ coal seam gas content Direct desorption method Gas component Sorption capacity Coal and gas outburst
下载PDF
Evaluation of roof cutting by directionally single cracking technique in automatic roadway formation for thick coal seam mining
16
作者 Yubing Gao Qiukai Gai +2 位作者 Xingxing Zhang Xun Xi Manchao He 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第5期137-157,共21页
Automatic roadway formation by roof cutting is a sustainable nonpillar mining method that has the potential to increase coal recovery,reduce roadway excavation and improve mining safety.In this method,roof cutting is ... Automatic roadway formation by roof cutting is a sustainable nonpillar mining method that has the potential to increase coal recovery,reduce roadway excavation and improve mining safety.In this method,roof cutting is the key process for stress relief,which significantly affects the stability of the formed roadway.This paper presents a directionally single cracking(DSC)technique for roof cutting with considerations of rock properties.The mechanism of the DSC technique was investi-gated by explicit finite element analyses.The DSC technique and roof cutting parameters were evaluated by discrete element simulation and field experiment.On this basis,the optimized DSC technique was tested in the field.The results indicate that the DSC technique could effectively control the blast-induced stress distribution and crack propagation in the roof rock,thus,achieve directionally single cracking on the roadway roof.The DsC technique for roof cutting with optimized parameters could effectively reduce the deformation and improve the stability of the formed roadway.Field engineering application verified the feasibility and effectiveness of the evaluated DSC technique for roof cutting. 展开更多
关键词 No pillar mining Automatic roadway formation Directionally single cracking Roof cutting Roadway stability-Thick coal seam mining
下载PDF
Automation Technology in Welding Seam Welding Machining Design
17
作者 LEI Dongyue 《International Journal of Plant Engineering and Management》 2023年第3期129-144,共16页
With the continuous development of society,the gradual improvement of mechanical automation technology has been introduced into the production of many enterprises in China,which has had a great impact on the increase ... With the continuous development of society,the gradual improvement of mechanical automation technology has been introduced into the production of many enterprises in China,which has had a great impact on the increase of China′s gross national product.Applying mechanical automation technology greatly saves labor cost,improves working efficiency and the production level of enterprises,effectively promotes the development of enterprises,and increases the enterprise′s income.In addition,mechanical automation technology is closely related to product production⁃related technology and plays a very important role in the innovation of enterprise products.This article will briefly introduce the design and application of automation technology in welding seam welding design,and understand the development background,research status,current application and simulation design. 展开更多
关键词 automation technology welding seam welding
下载PDF
倾斜碎软煤层群煤层气协调开发关键技术-以艾维尔沟矿区为例 被引量:2
18
作者 梁运培 朱拴成 +4 位作者 陈亮 赵坤 孙东玲 陈建杰 张碧川 《煤炭科学技术》 EI CAS CSCD 北大核心 2024年第1期211-220,共10页
为了明确与倾斜碎软煤层开采条件相适配的煤与煤层气协调开发关键技术,基于倾斜碎软煤层群瓦斯难抽采与煤层群非对称采动特征,形成了与之匹配的非对称卸压时空协同“三孔四区五量”煤与煤层气协调开发模式,明确了非对称采动下煤与煤层... 为了明确与倾斜碎软煤层开采条件相适配的煤与煤层气协调开发关键技术,基于倾斜碎软煤层群瓦斯难抽采与煤层群非对称采动特征,形成了与之匹配的非对称卸压时空协同“三孔四区五量”煤与煤层气协调开发模式,明确了非对称采动下煤与煤层气协调开发策略,阐明了井上下联合煤与煤层气协调开发时空协同机制。针对倾斜碎软突出首采煤层消突困难的问题,优化了倾斜碎软煤层下向长钻孔施工工艺,研制了钻头电磁波无线随钻测量系统,实现了更高精度的钻孔轨迹防偏。针对非对称采动区地面井防护缺乏针对性的难题,阐明了非对称采动覆岩卸压破坏时空演化特征,获得了非对称采动下覆岩采动裂隙演化特征,确定了倾斜煤层地面井井位安全位置,研发了能够兼顾地面井稳定性和抽采效率双因素的采动区地面三开套管结构。应用结果表明:时空协同的“三孔四区五量”模式能够实现煤层气高效抽采,保障倾斜煤层群的抽掘采接替平衡;倾斜煤层下向钻孔递进式抽采方式拓展了递进式抽采的应用范围,破解了倾斜煤层煤层气抽采过程中的时间不协调问题;优化后的采动地面井维稳结构能够适应非对称采动作用,实现了采动区地面井煤层气高效抽采。上述成果在新疆焦煤集团艾维尔沟矿区得到推广应用,初步形成符合艾维尔沟矿区主要高瓦斯矿区倾斜煤层特点的煤层气抽采关键技术和典型模式。 展开更多
关键词 煤层气开发技术 下向钻孔 地面钻井 倾斜碎软煤层 非对称采动
下载PDF
煤层瓦斯含量测定技术及装备研究进展
19
作者 孙四清 杨帆 +1 位作者 郑玉岐 张庆利 《煤炭科学技术》 EI CAS CSCD 北大核心 2024年第4期164-176,共13页
瓦斯含量是煤与瓦斯突出危险预测、煤层瓦斯资源量估算、矿井瓦斯治理工程设计的重要参数。围绕如何在大区域准确快速测定煤层瓦斯含量,依托国家科技重大专项、国家自然科学基金和煤炭企业联合基金等项目科技攻关,在取样、测试方面取得... 瓦斯含量是煤与瓦斯突出危险预测、煤层瓦斯资源量估算、矿井瓦斯治理工程设计的重要参数。围绕如何在大区域准确快速测定煤层瓦斯含量,依托国家科技重大专项、国家自然科学基金和煤炭企业联合基金等项目科技攻关,在取样、测试方面取得了一定进展。主要表现在如下4个方面:①煤层瓦斯含量测定取样经历了孔口接样、岩心管定点取样、压力引射定点取样和密闭取样4个阶段,密闭取样装备保压能力达到11.5 MPa,煤心直径达到38 mm;②针对不同煤层地质条件,发展形成了顺煤层定向长钻孔密闭取样、底板穿层钻孔密闭取样和顶(底)板梳状定向长钻孔密闭取样3种取样技术;③在河南焦作和山西晋城矿区硬煤层中,顺层定向长钻孔取样深度达到516 m,密闭取样法测得煤层瓦斯含量较常规取样法分别平均提高了0.44倍和1.04倍。在安徽淮南矿区碎软煤层中,穿层钻孔密闭取样深度达到209 m,测得煤层瓦斯含量较常规取样法平均提高了0.26倍;在安徽淮北矿区碎软煤层中,顶(底)板梳状钻孔密闭取样深度达到484 m,测得煤层瓦斯含量较常规取样法平均提高了0.19倍,密闭取样法在煤层瓦斯含量测定精度、探测范围上优于常规取样法;④在瓦斯含量测试方面,除了传统解吸法测试,发展了系列煤矿井下瓦斯含量快速测试装备,可实现最快30 min内测得煤层瓦斯含量,一般用于百米孔内的瓦斯含量测试。提出了煤层瓦斯含量测定密闭取样装备需向小型化、轻量化的方向发展,并能实现随钻密闭取样。在测试上,应根据实际情况确定合理的解吸终止限,并将测试装备和密闭取样装备进一步结合,以实现深孔瓦斯含量快速准确测定。密闭取样技术已成为煤层瓦斯含量大区域精准勘查、预测的主要手段,是煤炭安全高效开采的重要技术保障。 展开更多
关键词 煤层瓦斯含量 定点取样 密闭取样 碎软煤层 硬煤
下载PDF
鄂尔多斯盆地神木–佳县区块深部煤层气地质特征及勘探开发潜力 被引量:1
20
作者 李国永 姚艳斌 +5 位作者 王辉 孟令箭 李珮杰 张永超 王建伟 马立民 《煤田地质与勘探》 EI CAS CSCD 北大核心 2024年第2期70-80,共11页
我国深部(以下均指埋深大于2000 m)煤层气资源丰富,勘探开发潜力巨大。与中浅部相比,深部煤层气在富集成藏规律与开发方式方面均具有显著的差异性,急需针对重点区块开展解剖性分析研究。神木–佳县区块位于鄂尔多斯盆地东北部,目前尚处... 我国深部(以下均指埋深大于2000 m)煤层气资源丰富,勘探开发潜力巨大。与中浅部相比,深部煤层气在富集成藏规律与开发方式方面均具有显著的差异性,急需针对重点区块开展解剖性分析研究。神木–佳县区块位于鄂尔多斯盆地东北部,目前尚处于深部煤层气勘探的起步阶段,深部煤层气富集特征及开发潜力等尚不明确。基于研究区近期实施的地震资料、300余口井的测井资料和4口取心井的参数资料等,系统分析煤储层基础地质特征,总结煤层气富集主控因素与富集规律,类比剖析研究区深部煤层气勘探开发潜力。研究区深8号煤的镜质体反射率介于0.7%~1.8%,大部分区域煤层演化已处于热解生气高峰,区域上煤层净煤厚度高达7~8 m,煤层发育稳定,构造相对简单、水动力封闭性较强、顶底板封盖条件较好,为煤层气大面积连续成藏提供了优越条件,其中佳县南区的煤层气资源条件最好。与鄂尔多斯盆地东部其他区块深部煤层相比,研究区煤层中游离气占比明显更高(15.21%~46.47%),煤层中吸附气主要受吸附压力封存控制,而游离气受毛管力封闭与浮力重力分异双重控制,两种封存机制共同决定了深部煤层含气量的垂向分带与平面分区,以佳县南部为例总结了吸附气吸附压力主控、游离气毛管压力封闭与重力分异耦合控制的典型深部煤层气富集模式。与临兴区块和大宁–吉县区块类比分析结果表明,神木–佳县区块具有较好的煤层气资源基础、储层改造条件和高产潜力,预示了此区块深部煤层气规模化开发的美好前景。此外,大宁–吉县区块深部属典型的高煤阶煤,而神木–佳县深部为中煤阶煤,因此,该研究认识进一步丰富完善了深部煤层气富集理论,对于全国深部煤层气勘探开发实践有重要指示意义。 展开更多
关键词 深部(层)煤层气 鄂尔多斯盆地东部 神木-佳县 深8号煤 煤层气富集机制
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部