The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization ...The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization related to various hydrothermal fluid circulations. Petromineralogical studies indicate a rich mineral paragenesis with a minimum of seven mineralization phases and, at least, six pyrite generations. As is also the case for galena and native silver, native gold is observed for the first time as inclusion in quartz which opens up, thus, new perspectives for prospecting and evaluating the potential for noble metals associated with the mineralization. Scanning Electron Microscope--Energy Dispersive Spectroscopy and Transmission electron microscopy analyses show, in addition, a large incorporation of trace elements, including Ag and Au, in mineral structures such as fahlores(tetrahedrite-tennantite) and chalcopyrite ones. The mineral/mineral associations, used as geothermometers, gave estimated temperatures for the mineralizing fluids varying from 254 to 330 ℃ for phase Ⅲ, from 254 to 350 ℃ for phase Ⅳ, and from 200 to 300 ℃ for phases Ⅴ and Ⅵ. The seventh and last identified mineralization phase, marked by a deposit of native gold, reflects a drop in the mineralizing fluid’s temperature(< 200 ℃) compatible with boiling conditions. Such results open up perspectives for the development of precious metal research and the revaluation of the Cu–Fe ore deposit at the Ain El Bey abandoned mine, as well as at the surrounding areas fitting in the geodynamic framework of the Africa-Europe plate boundary.展开更多
Considering the influence of the streaming potential and electroviscous effects, the analytical solutions for electromagnetohydrodynamic (EMHD) flows in parallel plate microchannels are obtained. The electrolyte solut...Considering the influence of the streaming potential and electroviscous effects, the analytical solutions for electromagnetohydrodynamic (EMHD) flows in parallel plate microchannels are obtained. The electrolyte solutions in the microchannels are taken as generalized Maxwell fluids, and slip boundary conditions are adopted. To accurately analyze the EMHD flow characteristics, the variation trends of the electroviscous effects with the corresponding parameters must be understood. The results show that the electroviscous effects increase with the increase in the relaxation time De, the slip coefficient , and the wall zeta potential 0. However, the increase in the inverse of the electrical double-layer (EDL) thickness K, the electrical oscillating Reynolds number Re, and the ionic P'eclet number Pe can decrease the electroviscous effects. We also demonstrate that the electroviscous effect on the EMHD flows of generalized Maxwell fluids is larger than that of Newtonian fluids. This work will be useful in designing EMHD flows in parallel plate microchannels.展开更多
Tight and shale oil reservoirs are characterized by small pore throats,low porosity,and low permeability,which must be stimulated to increase production.Fluidflow experiences a multi-scale transport process,starting fr...Tight and shale oil reservoirs are characterized by small pore throats,low porosity,and low permeability,which must be stimulated to increase production.Fluidflow experiences a multi-scale transport process,starting from the matrix pore throats,extending to the natural fractures,and reaching the hydraulic fractures.Initially,tight and shale oil wells exhibit high production rates after hydraulic fracturing.However,this rapidly decreases due to insufficient energy in the reservoir,as well as formation damage to the reservoir,which impedes the multi-scale transport process.Consequently,effective systems for low-damage slickwater fracturingfluids and clean fracturingfluids to ensure the scale and effective development of tight and shale oil reservoirs after volume stimulation have been widely used.The pressure decay method and high back pressure displacement method have provided the valuable foundations for selecting fracturingfluids for tight and shale oil reservoirs.Nonetheless,challenges such as slowfluid transfer unpropped fracture closure,and water-phase trapping damage in tight and shale oil reservoirs need to be addressed urgently.Therefore,integrating fracture preservation,energy enhancement,and damage removal concepts will be essential for successful reservoir stimulation in tight and shale oil reservoirs.Additionally,exploring matching formation damage evaluation and fracturingfluid optimization technologies is crucial to achieving the efficient development of tight and shale oil reservoirs.These will all improve fracture stimulation effects and reservoir recovery,ultimately maxi-mizing the reservoir potential.展开更多
UniECAD is an integrated electronic CAD system, the user interfaCe develotwent system is the key of the integration of UniECAD. This paper presents the architecture of GUIDS, a graphical user interface development sys...UniECAD is an integrated electronic CAD system, the user interfaCe develotwent system is the key of the integration of UniECAD. This paper presents the architecture of GUIDS, a graphical user interface development system in UniECAD, and then discusses a series of new techniques and methods in the design and the implementation of this system around the following aspects: the editing environment of interface elements, the implementation of dialogue control and the automatic generation of interface code. As an example, the generation of the main interfaces of UniECAD shows the procedure of the development of user interfaces with this development system.展开更多
In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be use...In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.展开更多
A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing.The pressure drop of Cross-over-Disc is 12–26 times as large as that of empty pipe with equivalent...A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing.The pressure drop of Cross-over-Disc is 12–26 times as large as that of empty pipe with equivalent diameter and length.The mixing performance of Cross-over-Disc with 14 elements has been investigated in the viscosity range of 190–250 Pa·s by decoloration method,and the gray analysis of images shows that mixing inhomogeneity is about 7.5%and 9.4%for the mixing ratio of 5∶1 and 10∶1,respectively.Furthermore,mixing inhomogeneity for a combination of static mixing elements(four from Cross-over-Disc and three pairs from Sulzer-type)can be decreased to 2.1%–3.1%within a reasonable range of pressure drop.展开更多
The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold d...The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province.展开更多
本文从RFID(Radio Frequency Identification,无线射频识别技术)的关键技术之一射频标签序号防碰撞入手,先介绍了常用的二进制防碰撞算法,针对其在终端射频卡数量越多,UID(Ubiquitous Identifications,身份识别标签)位数越多,传送时间...本文从RFID(Radio Frequency Identification,无线射频识别技术)的关键技术之一射频标签序号防碰撞入手,先介绍了常用的二进制防碰撞算法,针对其在终端射频卡数量越多,UID(Ubiquitous Identifications,身份识别标签)位数越多,传送时间越长的缺点;提出了二进制防碰撞算法的改进算法,改进算法与传统算法相比,在标签位数逐渐增多的情况下,其查询次数增加速度明显减慢;最后通过仿真给以证实。展开更多
To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and ...To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and a dis-crete element method.Afluid-solid coupling numerical model has been introduced accordingly,and its accuracy has been validated through comparison of theoretical and numerical solutions.For different fracture forms(a single fracture,a branch fracture,and a fracture network),the influence of the time-varying viscosity on the slurry length range has been investigated,considering the change in the fracture aperture.The results show that under different fracture forms and the same grouting process conditions,the influence of the time-varying viscosity on the seepage length is 0.350 m.展开更多
基金funded by the “Laboratoire de Recherche Ressources, Matériaux et Ecosystémes”, University of Carthage 7021 Zarzouna, Bizerte, Tunisia
文摘The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization related to various hydrothermal fluid circulations. Petromineralogical studies indicate a rich mineral paragenesis with a minimum of seven mineralization phases and, at least, six pyrite generations. As is also the case for galena and native silver, native gold is observed for the first time as inclusion in quartz which opens up, thus, new perspectives for prospecting and evaluating the potential for noble metals associated with the mineralization. Scanning Electron Microscope--Energy Dispersive Spectroscopy and Transmission electron microscopy analyses show, in addition, a large incorporation of trace elements, including Ag and Au, in mineral structures such as fahlores(tetrahedrite-tennantite) and chalcopyrite ones. The mineral/mineral associations, used as geothermometers, gave estimated temperatures for the mineralizing fluids varying from 254 to 330 ℃ for phase Ⅲ, from 254 to 350 ℃ for phase Ⅳ, and from 200 to 300 ℃ for phases Ⅴ and Ⅵ. The seventh and last identified mineralization phase, marked by a deposit of native gold, reflects a drop in the mineralizing fluid’s temperature(< 200 ℃) compatible with boiling conditions. Such results open up perspectives for the development of precious metal research and the revaluation of the Cu–Fe ore deposit at the Ain El Bey abandoned mine, as well as at the surrounding areas fitting in the geodynamic framework of the Africa-Europe plate boundary.
基金Project supported by the National Natural Science Foundation of China(Nos.11772162 and11472140)the Inner Mongolia Autonomous Region Grassland Talent of China(No.12000-12102013)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2016MS0106)
文摘Considering the influence of the streaming potential and electroviscous effects, the analytical solutions for electromagnetohydrodynamic (EMHD) flows in parallel plate microchannels are obtained. The electrolyte solutions in the microchannels are taken as generalized Maxwell fluids, and slip boundary conditions are adopted. To accurately analyze the EMHD flow characteristics, the variation trends of the electroviscous effects with the corresponding parameters must be understood. The results show that the electroviscous effects increase with the increase in the relaxation time De, the slip coefficient , and the wall zeta potential 0. However, the increase in the inverse of the electrical double-layer (EDL) thickness K, the electrical oscillating Reynolds number Re, and the ionic P'eclet number Pe can decrease the electroviscous effects. We also demonstrate that the electroviscous effect on the EMHD flows of generalized Maxwell fluids is larger than that of Newtonian fluids. This work will be useful in designing EMHD flows in parallel plate microchannels.
基金support from the Natural Science Foundation of China(No.51674209)the Sichuan Province Youth Science and Technology Innovation Team project(No.2021JDTD0017)are greatly appreciated.
文摘Tight and shale oil reservoirs are characterized by small pore throats,low porosity,and low permeability,which must be stimulated to increase production.Fluidflow experiences a multi-scale transport process,starting from the matrix pore throats,extending to the natural fractures,and reaching the hydraulic fractures.Initially,tight and shale oil wells exhibit high production rates after hydraulic fracturing.However,this rapidly decreases due to insufficient energy in the reservoir,as well as formation damage to the reservoir,which impedes the multi-scale transport process.Consequently,effective systems for low-damage slickwater fracturingfluids and clean fracturingfluids to ensure the scale and effective development of tight and shale oil reservoirs after volume stimulation have been widely used.The pressure decay method and high back pressure displacement method have provided the valuable foundations for selecting fracturingfluids for tight and shale oil reservoirs.Nonetheless,challenges such as slowfluid transfer unpropped fracture closure,and water-phase trapping damage in tight and shale oil reservoirs need to be addressed urgently.Therefore,integrating fracture preservation,energy enhancement,and damage removal concepts will be essential for successful reservoir stimulation in tight and shale oil reservoirs.Additionally,exploring matching formation damage evaluation and fracturingfluid optimization technologies is crucial to achieving the efficient development of tight and shale oil reservoirs.These will all improve fracture stimulation effects and reservoir recovery,ultimately maxi-mizing the reservoir potential.
文摘UniECAD is an integrated electronic CAD system, the user interfaCe develotwent system is the key of the integration of UniECAD. This paper presents the architecture of GUIDS, a graphical user interface development system in UniECAD, and then discusses a series of new techniques and methods in the design and the implementation of this system around the following aspects: the editing environment of interface elements, the implementation of dialogue control and the automatic generation of interface code. As an example, the generation of the main interfaces of UniECAD shows the procedure of the development of user interfaces with this development system.
基金supported by the National Natural Science Foundation of China(No.11971152)the Fundamental Research Funds for the Universities of Henan Province(No.NSFRF180421)。
文摘In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.
基金financial support from the Innovative Research Team in University(IRT0721)the Programme of Introducing Talents of Discipline to Universities(111 Project)(B08021).
文摘A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing.The pressure drop of Cross-over-Disc is 12–26 times as large as that of empty pipe with equivalent diameter and length.The mixing performance of Cross-over-Disc with 14 elements has been investigated in the viscosity range of 190–250 Pa·s by decoloration method,and the gray analysis of images shows that mixing inhomogeneity is about 7.5%and 9.4%for the mixing ratio of 5∶1 and 10∶1,respectively.Furthermore,mixing inhomogeneity for a combination of static mixing elements(four from Cross-over-Disc and three pairs from Sulzer-type)can be decreased to 2.1%–3.1%within a reasonable range of pressure drop.
基金supported by the National Natural Science Foundation of China(42273063)the Young Elite Scientists Sponsorship(YESS)Program of the China Association for Science and Technology(YESS20220661)+1 种基金Fundamental Research Funds for Central Universities(FRF-IDRY-23-004)the Natural Science Foundation of Shandong Province,China(ZR2022QD050).
文摘The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province.
文摘本文从RFID(Radio Frequency Identification,无线射频识别技术)的关键技术之一射频标签序号防碰撞入手,先介绍了常用的二进制防碰撞算法,针对其在终端射频卡数量越多,UID(Ubiquitous Identifications,身份识别标签)位数越多,传送时间越长的缺点;提出了二进制防碰撞算法的改进算法,改进算法与传统算法相比,在标签位数逐渐增多的情况下,其查询次数增加速度明显减慢;最后通过仿真给以证实。
基金supported by the National Natural Science Foundation of China(Grant Numbers:U22A20234,42277170)the Key Research and Development Project of Hubei Province(Grant Number:2020BCB073).
文摘To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and a dis-crete element method.Afluid-solid coupling numerical model has been introduced accordingly,and its accuracy has been validated through comparison of theoretical and numerical solutions.For different fracture forms(a single fracture,a branch fracture,and a fracture network),the influence of the time-varying viscosity on the slurry length range has been investigated,considering the change in the fracture aperture.The results show that under different fracture forms and the same grouting process conditions,the influence of the time-varying viscosity on the seepage length is 0.350 m.
