Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery a...Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC.展开更多
The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force betwe...The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force between the two types of minerals and air bubbles determines the separation efficiency.In this paper,based on the extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory,the van der Waals,electrostatic and hydrophobic interaction between particles of the four minerals mentioned above and air bubbles in collectorless solution were calculated first,and then diaspore and kaolinite were taken as examples to analyze the influence of various factors such as electrolyte concentration,mineral particle size,air bubble size,collector type(dodecylamine hydrochloride(DAH)and sodium oleate(NaOL))and concentration,and pulp pH on the interactions between the particles of valuable mineral and gangue minerals and air bubbles.The results showed that the total extended DLVO interactions between the four minerals and air bubbles were repulsive in most cases in collectorless solution.The increase in electrolyte concentration reduced the interaction force or even changed the direction of the force under certain circumstances.The addition of DAH and NaOL can reduce the adhesion energy barrier of kaolinitebubble and diaspore-bubble respectively.Each type of minerals exhibited a specific interface interaction response with air bubbles in each collector with different pH values.The research results have theoretical guiding significance for the optimization and directional control of diasporic bauxite flotation conditions.展开更多
Stone coal is a special resource, because it is associated with a variety of rare metal elements. The elemental geochemical characteristics of stone coal can provide useful information for the study of its formation a...Stone coal is a special resource, because it is associated with a variety of rare metal elements. The elemental geochemical characteristics of stone coal can provide useful information for the study of its formation and evolution history. The content of rare earth elements in stone coal has been the focus of attention. Stone coal is widely distributed in southern Shaanxi province of China. In order to study the content and distribution of rare earth elements in stone coal, and provide a plan for the comprehensive development and utilization of stone coal, this study tested the rare earth elements content of stone coal, parting and coal ash samples, respectively, compared the content of rare earth elements in stone coal, parting, coal ash with the mean value of China coal, the mean value of world coal and the abundance value of upper crust, and discussed the features of rare earth elements content in different types of samples in southern Shaanxi province of China. The average contents of rare earth elements in the samples of stone coal, parting and coal ash were calculated, and the enrichment coefficients of the samples with the mean value of China coal, the mean value of world coal and the abundance value of upper crust were listed. The distribution rules and characteristics of the contents of rare earth elements in different types of samples in southern Shaanxi province of China were summarized.展开更多
During the processes of methane adsorption and desorption,the internal structure of coal changes,accordingly leading to changes in electrical conductivity.In this paper,using low rank coal seams of the Yan'an Form...During the processes of methane adsorption and desorption,the internal structure of coal changes,accordingly leading to changes in electrical conductivity.In this paper,using low rank coal seams of the Yan'an Formation in the Dafbsi field as the research subject,the relationship between coal resistivity,methane adsorption quantity,and equilibrium pressure is analyzed through proximate analysis,mercury injection tests,low temperature liquid nitrogen adsorption tests,and coal resistivity measurements during methane adsorption and desorption.The results show that during the process of pressure rise and methane adsorption,the conductivity of coal increases,resulting from heat release from methane adsorption,coal matrix swelling and adsorbed water molecules replaced by methane,but the resistivity reduction gradually decreases.The relationship between coal resistivity and methane adsorption quantity and equilibrium pressure can be described by a quadratic function.During the processes of depressurization and desorption,the resistivity of coal rebounds slightly,due to decalescence of methane desorption,coal matrix shrinkage and water-gas displacement,and the relationship coincides with a linear function.Methane adsorption leads to irreversible changes in coal internal structure and enhances the coal conductivity,and resistivity can not be restored to the initial level even after methane desorption.The resistivity and reduction rate of durain are higher than those of vitrain,with relatively greater homogeneous pore throat structure and fewer charged particles in the double electric layer.In addition,moisture can enhance the conductivity of coal and makes it change more complexly during methane adsorption and desorption.展开更多
To accelerate the achievement of China’s carbon neutrality goal and to study the factors affecting the geologic CO_(2)storage in the Ordos Basin,China’s National Key R&D Programs propose to select the Chang 6 oi...To accelerate the achievement of China’s carbon neutrality goal and to study the factors affecting the geologic CO_(2)storage in the Ordos Basin,China’s National Key R&D Programs propose to select the Chang 6 oil reservoir of the Yanchang Formation in the Ordos Basin as the target reservoir to conduct the geologic carbon capture and storage(CCS)of 100000 t per year.By applying the basic theories of disciplines such as seepage mechanics,multiphase fluid mechanics,and computational fluid mechanics and quantifying the amounts of CO_(2)captured in gas and dissolved forms,this study investigated the effects of seven factors that influence the CO_(2)storage capacity of reservoirs,namely reservoir porosity,horizontal permeability,temperature,formation stress,the ratio of vertical to horizontal permeability,capillary pressure,and residual gas saturation.The results show that the sensitivity of the factors affecting the gas capture capacity of CO_(2)decreases in the order of formation stress,temperature,residual gas saturation,horizontal permeability,and porosity.Meanwhile,the sensitivity of the factors affecting the dissolution capture capacity of CO_(2)decreases in the order of formation stress,residual gas saturation,temperature,horizontal permeability,and porosity.The sensitivity of the influencing factors can serve as the basis for carrying out a reasonable assessment of sites for future CO_(2)storage areas and for optimizing the design of existing CO_(2)storage areas.The sensitivity analysis of the influencing factors will provide basic data and technical support for implementing geologic CO_(2)storage and will assist in improving geologic CO_(2)storage technologies to achieve China’s carbon neutralization goal.展开更多
Nanoscale pore characteristics of the Upper Permian Longtan transitional mudrocks and their equivalent strata Wujiaping Formation marine mudrocks in and around the eastern Sichuan Basin was investigated using field em...Nanoscale pore characteristics of the Upper Permian Longtan transitional mudrocks and their equivalent strata Wujiaping Formation marine mudrocks in and around the eastern Sichuan Basin was investigated using field emission scanning electron microscopy(FE-SEM)and low-pressure N2 adsorption experiments.The results indicate that the Upper Permian mudrock is at a mature stage with total organic carbon(TOC)values ranging between 0.47%and 12.3%.The Longtan mudrocks mainly contain vitrinite,and their mineral composition is primarily clay.In contrast,the Wujiaping mudrocks are dominated by sapropelinite and solid bitumen,and their mineral compositions are mainly quartz and a notably high amount of pyrite.The FE-SEM reveals that clay mineral pores and microcracks are the common pore types in the Longtan mudrocks.The specific surface area and pore volume depend on the clay content but are negatively correlated with the TOC.The generation of nanometer pores in the Longtan mudrocks is caused by high clay mineral contents.Meanwhile,the Wujiaping mudrock mainly contains OM pores,and the pore parameters are positively correlated with the TOC.The OM pore development exhibits remarkable differences in the Longtan and Wujiaping mudrocks,which might be related to their sedimentary facies and maceral fractions.Vitrinite and inertinite appear as discrete particles in these mudrocks and cannot generate pores during thermal maturation.Sapropelinite often contains many secondary pores,and solid bitumen with large particles,usually with several pores,is not the major contributor to the pore system of the investigated mudrock.展开更多
The Ordos Basin is an important intracontinental sedimentary basin in China,containing a significant amount of coal,oil,and natural gas.This study analyzed the sedimentary environment,sedimentary facies,parent materia...The Ordos Basin is an important intracontinental sedimentary basin in China,containing a significant amount of coal,oil,and natural gas.This study analyzed the sedimentary environment,sedimentary facies,parent material type,maturity,and carbon isotopic composition of the coal-bearing organic matter using gas chromatography–mass spectrometry(GC–MS)and stable isotope ratio mass spectrometry.The source of oil occurring in the No.2 coal seam of the Jurassic Yan’an Formation(An-1 oil)and its accumulation model were also investigated.The results show that the relative abundances of C_(27),C_(28),and C_(29) steranes in the An-1 oil are 43.8%,33.0%,and 23.2%,respectively.The tricyclic terpanes,C_(29)20S/(20S+20R),and C_(29)ββ/(ββ+αα)contents of the An-1 oil are 31.4%−34.8%,0.85 and 0.81,respectively.Pr/n-C17,Ph/n-C18,and Pr/Ph values are 0.34,0.42,and 0.87,respectively.Biomarker parameters indicate that the An-1 oil mainly comes from the plankton source rock deposited in the freshwater lake facies and a reducing environment,which has evolved to maturity.The correlation of oil-oil indicates that the An-1 oil is homologous to the Chang-7 oil(Chang-7 member of the Triassic Yanchang Formation).The correlation of oil-source rock presents that the An-1 oil is generated from the Yanchang Formation(Chang-6 and Chang-7 source rocks)and occurred in the coal seam during the stage of stratum uplift since the Early of Late Cretaceous.The distribution characteristics of δ13C group components in the An-1 oil and Chang-7 oil also reveal the fractionation phenomenon during the migration of crude oil.展开更多
As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been ...As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been the ability to predict landslide susceptibility,which can be used to design schemes of land exploitation and urban development in mountainous areas.In this study,the teaching-learning-based optimization(TLBO)and satin bowerbird optimizer(SBO)algorithms were applied to optimize the adaptive neuro-fuzzy inference system(ANFIS)model for landslide susceptibility mapping.In the study area,152 landslides were identified and randomly divided into two groups as training(70%)and validation(30%)dataset.Additionally,a total of fifteen landslide influencing factors were selected.The relative importance and weights of various influencing factors were determined using the step-wise weight assessment ratio analysis(SWARA)method.Finally,the comprehensive performance of the two models was validated and compared using various indexes,such as the root mean square error(RMSE),processing time,convergence,and area under receiver operating characteristic curves(AUROC).The results demonstrated that the AUROC values of the ANFIS,ANFIS-TLBO and ANFIS-SBO models with the training data were 0.808,0.785 and 0.755,respectively.In terms of the validation dataset,the ANFISSBO model exhibited a higher AUROC value of 0.781,while the AUROC value of the ANFIS-TLBO and ANFIS models were 0.749 and 0.681,respectively.Moreover,the ANFIS-SBO model showed lower RMSE values for the validation dataset,indicating that the SBO algorithm had a better optimization capability.Meanwhile,the processing time and convergence of the ANFIS-SBO model were far superior to those of the ANFIS-TLBO model.Therefore,both the ensemble models proposed in this paper can generate adequate results,and the ANFIS-SBO model is recommended as the more suitable model for landslide susceptibility assessment in the study area considered due to its excellent accuracy and efficiency.展开更多
Objective With the discovery of the Fuling shale gas field and the realization of commercial exploitation, the prediction of shale gas well production state has attracted wide attention of scholars at home and abroad.
Gully erosion is a disruptive phenomenon which extensively affects the Iranian territory,especially in the Northern provinces.A number of studies have been recently undertaken to study this process and to predict it o...Gully erosion is a disruptive phenomenon which extensively affects the Iranian territory,especially in the Northern provinces.A number of studies have been recently undertaken to study this process and to predict it over space and ultimately,in a broader national effort,to limit its negative effects on local communities.We focused on the Bastam watershed where 9.3%of its surface is currently affected by gullying.Machine learning algorithms are currently under the magnifying glass across the geomorphological community for their high predictive ability.However,unlike the bivariate statistical models,their structure does not provide intuitive and quantifiable measures of environmental preconditioning factors.To cope with such weakness,we interpret preconditioning causes on the basis of a bivariate approach namely,Index of Entropy.And,we performed the susceptibility mapping procedure by testing three extensions of a decision tree model namely,Alternating Decision Tree(ADTree),Naive-Bayes tree(NBTree),and Logistic Model Tree(LMT).We dichotomized the gully information over space into gully presence/absence conditions,which we further explored in their calibration and validation stages.Being the presence/absence information and associated factors identical,the resulting differences are only due to the algorithmic structures of the three models we chose.Such differences are not significant in terms of performances;in fact,the three models produce outstanding predictive AUC measures(ADTree=0.922;NBTree=0.939;LMT=0.944).However,the associated mapping results depict very different patterns where only the LMT is associated with reasonable susceptibility patterns.This is a strong indication of what model combines best performance and mapping for any natural hazard-oriented application.展开更多
The complex resistivity of coal and related rocks contains abundant physical property information,which can be indirectly used to study the lithology and microstructure of these materials.These aspects are closely rel...The complex resistivity of coal and related rocks contains abundant physical property information,which can be indirectly used to study the lithology and microstructure of these materials.These aspects are closely related to the fluids inside the considered coal rocks,such as gas,water and coalbed methane.In the present analysis,considering different lithological structures,and using the Cole-Cole model,a forward simulation method is used to study different physical parameters such as the zero-frequency resistivity,the polarizability,the relaxation time,and the frequency correlation coefficient.Moreover,using a least square technique,a complex resistivity“inversion”algorithm is written.The comparison of the initial model parameters and those obtained after inversion is used to verify the stability and accuracy of such approach.The method is finally applied to primary-structure coal considered as the experimental sample for complex resistivity measurements.展开更多
Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in con...Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in considering of the attractive optical properties.In this work,we present a CDs based fluorescent sensor from polyvinylpyrrolidone,citric acid,and methionine as precursors by hydrothermal approach.The selective quantifying of Fe^(3+)and ascorbic acid(AA)are based on the fluorescent on-off-on process,in which the fluorescent quenching is induced by the coordination of the Fe^(3+)on the surface of the CDs,while the fluorescence recovery is mainly attributed to redox reaction between Fe^(3+)and AA,breaking the coordination and bringing the fluorescence back.Inspired by the good water solubility and biocompatibility,significant photostability,superior photobleaching resistance as well as high selectivity,sensitivity,and interference immunity,which are constructed mainly from the N,S-doping and methionine surface functionalization,the CDs have not only been employed as fluorescence ink in multiple anticounterfeiting printing and confidential document writing or transmitting,but also been developed as promising fluorescence sensors in solution and solid by CDs doped test strips and hydrogels for effectively monitoring and removing of Fe^(3+)and AA in environmental aqueous solution.The CDs have been also implemented as effective diagnostic candidates for imaging and tracking of Fe^(3+)and AA in living cells,accelerating the understanding of their function and importance in related biological processes for the prevention and treatment specific diseases.展开更多
Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent years.However,the current construction methods are complicated and resulting PLs possess high viscos...Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent years.However,the current construction methods are complicated and resulting PLs possess high viscosity values,which cannot meet the requirements of practical industrial applications.Herein,we demonstrate a generalizable and simple strategy to prepare type III PLs with low viscosity based on the rule of“like dissolves like”.Specifically,the monoglycidyl ether terminated polydimethylsiloxane(denoted by E-PDMS)is attached to the surface of Universitetet i Oslo(UiO)-66-NH_(2)via covalent linkage,constructing the pore generator(UiO-66-NH_(2)-E-PDMS,denoted by P-UiO-66).Then,P-UiO-66 is dispersed into different types and amounts of sterically hindered solvents(PDMS400 or PDMS6000),obtaining a series of type III PLs(denoted by P-UiO-66-PLs)with permanent cavities and low viscosities.The gas sorption-desorption test shows that P-UiO-66-PLs have an enormous potential for CO_(2)/N_(2) selective separation.Besides,the porosity of P-UiO-66-PLs and the CO_(2)sorption mechanism are demonstrated by molecular simulation.Furthermore,the generality of the synthesis strategy is confirmed by the successful construction of PLs using two other amino-metal-organic frameworks(MOFs)(MIL-53(Al)-NH_(2)and MIL-88B(Fe)-NH_(2)).Importantly,it’s worth noting that the strategy based on the rule of“like dissolves like”sheds light on the preparation of other types of PLs for task-specific applications.展开更多
Here,we describe a new primitive Erinaceidae species,Oligoechinus lanzhouensis n.gen.n.sp.,based on a specimen from late Oligocene strata of the Lanzhou Basin,Gansu Province.Its characteristics are as follows:the M1 w...Here,we describe a new primitive Erinaceidae species,Oligoechinus lanzhouensis n.gen.n.sp.,based on a specimen from late Oligocene strata of the Lanzhou Basin,Gansu Province.Its characteristics are as follows:the M1 width is longer than the length,the metastyle extends far disto-labially,the posterior margin has strong curve and a distinct metaconule that is connected to the protocone by a postprotocrista is located in the centre of the tooth.The posterior arm of the metaconule is poorly developed.In the P4,the pterion of the metastyle is less developed and the metacone is carinate.In addition,O.lanzhouensis has a premolar larger than the canine tooth(P2>C)and P3 had no molarisation,characters also possessed by Erinaceus.Overall,O.lanzhouensis was similar to Mioechinus based on architectural tooth features,demonstrating a closed genetic relationship.Fossil Erinaceidae are relatively rare before the Miocene.The discovery of O.lanzhouensis provides an important insight into the origin of Mioechinus in China and the early evolution of the Erinaceidae.Our analysis shows that a relatively recent ancestor of Mioechinus had probably existed in the early Oligocene and that O.Lanzhouensis was likely an ancestral type of Mioechinus gobiensis,and its systematic position should be located at a transitional position between Amphechinus and Mioechinus.展开更多
In order to suppress the surface wave in three-component seismic exploration, according to the polarization characteristics of body wave and surface wave, a time-frequency domain polarization filtering method based on...In order to suppress the surface wave in three-component seismic exploration, according to the polarization characteristics of body wave and surface wave, a time-frequency domain polarization filtering method based on wavelet transform was studied. A covariance matrix was constructed in the time-frequency domain for the three-component seismic data, measured the polarization parameters of seismic waves. Combining the corresponding eigenvalues and eigenvectors of the matrix, the elliptic rate and elevation angle were used as constraints, and the polarization filter function was built to separate the surface waves. The separated surface waves were inversely transformed and then were adaptively subtracted from the original records. After the polarization filtering suppressed the surface wave, the signal-to-noise ratio of the converted wave was effectively improved. It laid a good foundation for the next seismic data processing and seismic exploration development. The actual data processing results show that the method can effectively extract surface waves from three-component seismic records and avoid the interference of surface waves on seismic signals.展开更多
The material composition of geological samples is very complicated. Generally, the method for accurately determining trace elements in geological samples needs to digest the solid samples into liquid state, which is c...The material composition of geological samples is very complicated. Generally, the method for accurately determining trace elements in geological samples needs to digest the solid samples into liquid state, which is convenient for inductively coupled plasma mass spectrometry. The previous digestion method takes a long time and the operation process is complicated. The Ultra CLAVE microwave digestion instrument was used to digest the geological samples. The types and dosages of the acid used for digestion and the optimal conditions for instrumental testing were published. The results show that this method has short processing time, small data error, safer operation and good digestion effect. This method is suitable for geological sample analysis.展开更多
A facile hydrothermal strategy is adopted to synthesize the composite of NiCo-layered double hydroxide(NiCo-LDH)with biomass carbon as substrate for supercapacitor electrodes.The prepared NiCo@BC was characterized by ...A facile hydrothermal strategy is adopted to synthesize the composite of NiCo-layered double hydroxide(NiCo-LDH)with biomass carbon as substrate for supercapacitor electrodes.The prepared NiCo@BC was characterized by means of X-ray diffraction(XRD),scanning electronic microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy,and electrochemical tests.The SEM images demonstrated that numerous NiCo-LDH nanosheets directly grew on the surface of biomass carbon uniformly.Electrochemical tests indicated that the NiCo@BC electrode exhibited good capacitive behavior with a specific capacitance of 606.4 F/g at the current density of 0.5 A/g.In addition,the composite electrode showed excellent cyclic stability of 87.1%even after 1000 cycles.These results manifest that NiCo@BC nanocomposite is a promising candidate for the electrode material for future supercapacitor practical applications.展开更多
The development of compressible supercapacitors strongly relies on the design of electrode materials combining superior compressibility,high conductivity with the stable electrochemical cycling performance.In this wor...The development of compressible supercapacitors strongly relies on the design of electrode materials combining superior compressibility,high conductivity with the stable electrochemical cycling performance.In this work,we report a facile yet scalable strategy to construct a highly compressible supercapacitor by integrating the current collector,active materials and the separator into one device.We use the highly compressive melamine foam(MF)as scaffold and the Ti_(3)C_(2)T_(x)nanosheets as the active materials.Filling the few-layer Ti_(3)C_(2)T_(x)nanosheets into the skeleton of MF by capillary force followed by freeze-drying yields the MF/Ti_(3)C_(2)T_(x)composite with superior structural integrity that can be compressed at a large strain of 50%for 100 cycles.The electrochemical performances of the all-in-one supercapacitor were systematically investigated under diverse compression strains.The improved conductivity and reduced ion diffusion length allow the all-in-one supercapacitor to exhibit fast ion and electron kinetics even at high strain of 60%,delivering a maximal volumetric specific energy of 0.37 mWh∙cm^(-3)at power density of 0.42 mW∙cm^(-3)and extraordinary cycling performance during the 2,500 compression cycles.展开更多
基金the National Natural Science Foundation of China(No.52374279)the Natural Science Foundation of Shaanxi Province(No.2023-YBGY-055).
文摘Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC.
基金supported by the National Natural Science Foundation of China(No.51904240,51904239,52104268)the Natural Science Foundation of Shaanxi Province(No.2020JQ-752,2021JQ-571)+3 种基金the Postdoctoral Science Foundation of China(No.2019M653877XB)the Outstanding Youth Science Foundation of Xi’an University of Science and Technology(No.2019YQ3-08)the Huo Yingdong Education Foundation(No.171102)the 2019 Merit-based Science and Technology Project Foundation for Shannxi Overseas-educated Scholars(No.14).
文摘The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force between the two types of minerals and air bubbles determines the separation efficiency.In this paper,based on the extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory,the van der Waals,electrostatic and hydrophobic interaction between particles of the four minerals mentioned above and air bubbles in collectorless solution were calculated first,and then diaspore and kaolinite were taken as examples to analyze the influence of various factors such as electrolyte concentration,mineral particle size,air bubble size,collector type(dodecylamine hydrochloride(DAH)and sodium oleate(NaOL))and concentration,and pulp pH on the interactions between the particles of valuable mineral and gangue minerals and air bubbles.The results showed that the total extended DLVO interactions between the four minerals and air bubbles were repulsive in most cases in collectorless solution.The increase in electrolyte concentration reduced the interaction force or even changed the direction of the force under certain circumstances.The addition of DAH and NaOL can reduce the adhesion energy barrier of kaolinitebubble and diaspore-bubble respectively.Each type of minerals exhibited a specific interface interaction response with air bubbles in each collector with different pH values.The research results have theoretical guiding significance for the optimization and directional control of diasporic bauxite flotation conditions.
文摘Stone coal is a special resource, because it is associated with a variety of rare metal elements. The elemental geochemical characteristics of stone coal can provide useful information for the study of its formation and evolution history. The content of rare earth elements in stone coal has been the focus of attention. Stone coal is widely distributed in southern Shaanxi province of China. In order to study the content and distribution of rare earth elements in stone coal, and provide a plan for the comprehensive development and utilization of stone coal, this study tested the rare earth elements content of stone coal, parting and coal ash samples, respectively, compared the content of rare earth elements in stone coal, parting, coal ash with the mean value of China coal, the mean value of world coal and the abundance value of upper crust, and discussed the features of rare earth elements content in different types of samples in southern Shaanxi province of China. The average contents of rare earth elements in the samples of stone coal, parting and coal ash were calculated, and the enrichment coefficients of the samples with the mean value of China coal, the mean value of world coal and the abundance value of upper crust were listed. The distribution rules and characteristics of the contents of rare earth elements in different types of samples in southern Shaanxi province of China were summarized.
基金financially supported by the Independent Projects of the Key Lab. of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources of China (grants No. KF2019-2, ZKF2018-1, KF2018-4, ZP2018-2)the Major National Science and Technology Special Projects (grant No. 2016ZX05042004)+3 种基金the Projects Funded by China Postdoctoral Science Foundation (grant No. 2019M653873XB)the Natural Science Foundation Research Projects of Shaanxi Province (grant No. 2019JQ-245)the Doctoral Research Starting Foundation of Xi’an University of Science and Technology (grant No. 2016QDJ041)the Research Projects of the Geological Research Institute for Coal Green Mining of Xi’an University of Science and Technology (grant No. MTy2019-04)
文摘During the processes of methane adsorption and desorption,the internal structure of coal changes,accordingly leading to changes in electrical conductivity.In this paper,using low rank coal seams of the Yan'an Formation in the Dafbsi field as the research subject,the relationship between coal resistivity,methane adsorption quantity,and equilibrium pressure is analyzed through proximate analysis,mercury injection tests,low temperature liquid nitrogen adsorption tests,and coal resistivity measurements during methane adsorption and desorption.The results show that during the process of pressure rise and methane adsorption,the conductivity of coal increases,resulting from heat release from methane adsorption,coal matrix swelling and adsorbed water molecules replaced by methane,but the resistivity reduction gradually decreases.The relationship between coal resistivity and methane adsorption quantity and equilibrium pressure can be described by a quadratic function.During the processes of depressurization and desorption,the resistivity of coal rebounds slightly,due to decalescence of methane desorption,coal matrix shrinkage and water-gas displacement,and the relationship coincides with a linear function.Methane adsorption leads to irreversible changes in coal internal structure and enhances the coal conductivity,and resistivity can not be restored to the initial level even after methane desorption.The resistivity and reduction rate of durain are higher than those of vitrain,with relatively greater homogeneous pore throat structure and fewer charged particles in the double electric layer.In addition,moisture can enhance the conductivity of coal and makes it change more complexly during methane adsorption and desorption.
基金jointly supported by the National Key R&D Program of China (2018YFB0605503)the National Natural Science Foundation of China (51804112)+2 种基金the National Key R&D Program of China (2018YFC0807801)the Open Foundation of Key Laboratory of Coal Exploration and Comprehensive Utilization of Ministry of Natural Resources (KF2021-5)the Natural Science Foundation of Hunan Province of China (2018JJ3169).
文摘To accelerate the achievement of China’s carbon neutrality goal and to study the factors affecting the geologic CO_(2)storage in the Ordos Basin,China’s National Key R&D Programs propose to select the Chang 6 oil reservoir of the Yanchang Formation in the Ordos Basin as the target reservoir to conduct the geologic carbon capture and storage(CCS)of 100000 t per year.By applying the basic theories of disciplines such as seepage mechanics,multiphase fluid mechanics,and computational fluid mechanics and quantifying the amounts of CO_(2)captured in gas and dissolved forms,this study investigated the effects of seven factors that influence the CO_(2)storage capacity of reservoirs,namely reservoir porosity,horizontal permeability,temperature,formation stress,the ratio of vertical to horizontal permeability,capillary pressure,and residual gas saturation.The results show that the sensitivity of the factors affecting the gas capture capacity of CO_(2)decreases in the order of formation stress,temperature,residual gas saturation,horizontal permeability,and porosity.Meanwhile,the sensitivity of the factors affecting the dissolution capture capacity of CO_(2)decreases in the order of formation stress,residual gas saturation,temperature,horizontal permeability,and porosity.The sensitivity of the influencing factors can serve as the basis for carrying out a reasonable assessment of sites for future CO_(2)storage areas and for optimizing the design of existing CO_(2)storage areas.The sensitivity analysis of the influencing factors will provide basic data and technical support for implementing geologic CO_(2)storage and will assist in improving geologic CO_(2)storage technologies to achieve China’s carbon neutralization goal.
基金supported by the National NaturalScience Foundation of China(Grant No.41802163,41503033)Hunan Provincial Natural Science Foundation of China(Grant No.2018JJ3152)+1 种基金the Science and Technology Plan Project of Sichuan province(Grant No.2018JZ0003)the State Petroleum and Gas Specific Project(Grant No.2016ZX05061001-001)
文摘Nanoscale pore characteristics of the Upper Permian Longtan transitional mudrocks and their equivalent strata Wujiaping Formation marine mudrocks in and around the eastern Sichuan Basin was investigated using field emission scanning electron microscopy(FE-SEM)and low-pressure N2 adsorption experiments.The results indicate that the Upper Permian mudrock is at a mature stage with total organic carbon(TOC)values ranging between 0.47%and 12.3%.The Longtan mudrocks mainly contain vitrinite,and their mineral composition is primarily clay.In contrast,the Wujiaping mudrocks are dominated by sapropelinite and solid bitumen,and their mineral compositions are mainly quartz and a notably high amount of pyrite.The FE-SEM reveals that clay mineral pores and microcracks are the common pore types in the Longtan mudrocks.The specific surface area and pore volume depend on the clay content but are negatively correlated with the TOC.The generation of nanometer pores in the Longtan mudrocks is caused by high clay mineral contents.Meanwhile,the Wujiaping mudrock mainly contains OM pores,and the pore parameters are positively correlated with the TOC.The OM pore development exhibits remarkable differences in the Longtan and Wujiaping mudrocks,which might be related to their sedimentary facies and maceral fractions.Vitrinite and inertinite appear as discrete particles in these mudrocks and cannot generate pores during thermal maturation.Sapropelinite often contains many secondary pores,and solid bitumen with large particles,usually with several pores,is not the major contributor to the pore system of the investigated mudrock.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.42172200 and 41972183)the“Chunhui Plan”Cooperative Research for Ministry of Education.
文摘The Ordos Basin is an important intracontinental sedimentary basin in China,containing a significant amount of coal,oil,and natural gas.This study analyzed the sedimentary environment,sedimentary facies,parent material type,maturity,and carbon isotopic composition of the coal-bearing organic matter using gas chromatography–mass spectrometry(GC–MS)and stable isotope ratio mass spectrometry.The source of oil occurring in the No.2 coal seam of the Jurassic Yan’an Formation(An-1 oil)and its accumulation model were also investigated.The results show that the relative abundances of C_(27),C_(28),and C_(29) steranes in the An-1 oil are 43.8%,33.0%,and 23.2%,respectively.The tricyclic terpanes,C_(29)20S/(20S+20R),and C_(29)ββ/(ββ+αα)contents of the An-1 oil are 31.4%−34.8%,0.85 and 0.81,respectively.Pr/n-C17,Ph/n-C18,and Pr/Ph values are 0.34,0.42,and 0.87,respectively.Biomarker parameters indicate that the An-1 oil mainly comes from the plankton source rock deposited in the freshwater lake facies and a reducing environment,which has evolved to maturity.The correlation of oil-oil indicates that the An-1 oil is homologous to the Chang-7 oil(Chang-7 member of the Triassic Yanchang Formation).The correlation of oil-source rock presents that the An-1 oil is generated from the Yanchang Formation(Chang-6 and Chang-7 source rocks)and occurred in the coal seam during the stage of stratum uplift since the Early of Late Cretaceous.The distribution characteristics of δ13C group components in the An-1 oil and Chang-7 oil also reveal the fractionation phenomenon during the migration of crude oil.
基金supported by the National Natural Science Foundation of China(Grant Nos.41807192,41790441)Innovation Capability Support Program of Shaanxi(Grant No.2020KJXX-005)Natural Science Basic Research Program of Shaanxi(Grant Nos.2019JLM-7,2019JQ-094)。
文摘As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been the ability to predict landslide susceptibility,which can be used to design schemes of land exploitation and urban development in mountainous areas.In this study,the teaching-learning-based optimization(TLBO)and satin bowerbird optimizer(SBO)algorithms were applied to optimize the adaptive neuro-fuzzy inference system(ANFIS)model for landslide susceptibility mapping.In the study area,152 landslides were identified and randomly divided into two groups as training(70%)and validation(30%)dataset.Additionally,a total of fifteen landslide influencing factors were selected.The relative importance and weights of various influencing factors were determined using the step-wise weight assessment ratio analysis(SWARA)method.Finally,the comprehensive performance of the two models was validated and compared using various indexes,such as the root mean square error(RMSE),processing time,convergence,and area under receiver operating characteristic curves(AUROC).The results demonstrated that the AUROC values of the ANFIS,ANFIS-TLBO and ANFIS-SBO models with the training data were 0.808,0.785 and 0.755,respectively.In terms of the validation dataset,the ANFISSBO model exhibited a higher AUROC value of 0.781,while the AUROC value of the ANFIS-TLBO and ANFIS models were 0.749 and 0.681,respectively.Moreover,the ANFIS-SBO model showed lower RMSE values for the validation dataset,indicating that the SBO algorithm had a better optimization capability.Meanwhile,the processing time and convergence of the ANFIS-SBO model were far superior to those of the ANFIS-TLBO model.Therefore,both the ensemble models proposed in this paper can generate adequate results,and the ANFIS-SBO model is recommended as the more suitable model for landslide susceptibility assessment in the study area considered due to its excellent accuracy and efficiency.
基金Project of National Natural Science Foundation o f China (grant No.41503033)the Key Project of National Natural Science Foundation o f China (grant No.Ul 663202)
文摘Objective With the discovery of the Fuling shale gas field and the realization of commercial exploitation, the prediction of shale gas well production state has attracted wide attention of scholars at home and abroad.
文摘Gully erosion is a disruptive phenomenon which extensively affects the Iranian territory,especially in the Northern provinces.A number of studies have been recently undertaken to study this process and to predict it over space and ultimately,in a broader national effort,to limit its negative effects on local communities.We focused on the Bastam watershed where 9.3%of its surface is currently affected by gullying.Machine learning algorithms are currently under the magnifying glass across the geomorphological community for their high predictive ability.However,unlike the bivariate statistical models,their structure does not provide intuitive and quantifiable measures of environmental preconditioning factors.To cope with such weakness,we interpret preconditioning causes on the basis of a bivariate approach namely,Index of Entropy.And,we performed the susceptibility mapping procedure by testing three extensions of a decision tree model namely,Alternating Decision Tree(ADTree),Naive-Bayes tree(NBTree),and Logistic Model Tree(LMT).We dichotomized the gully information over space into gully presence/absence conditions,which we further explored in their calibration and validation stages.Being the presence/absence information and associated factors identical,the resulting differences are only due to the algorithmic structures of the three models we chose.Such differences are not significant in terms of performances;in fact,the three models produce outstanding predictive AUC measures(ADTree=0.922;NBTree=0.939;LMT=0.944).However,the associated mapping results depict very different patterns where only the LMT is associated with reasonable susceptibility patterns.This is a strong indication of what model combines best performance and mapping for any natural hazard-oriented application.
基金This research was funded by the National Natural Science Foundation under Grant No.[41974151]by the Jiangsu Province Natural Science Foundation under Grant No.[BK20181360]+1 种基金by the Major Scientific and Technological Innovation Project of Shandong Province of China under Grant No.[2019JZZY010820]by the Shaanxi Province Science and Technology Innovation Guidance Special No.[2020CGHJ-005].
文摘The complex resistivity of coal and related rocks contains abundant physical property information,which can be indirectly used to study the lithology and microstructure of these materials.These aspects are closely related to the fluids inside the considered coal rocks,such as gas,water and coalbed methane.In the present analysis,considering different lithological structures,and using the Cole-Cole model,a forward simulation method is used to study different physical parameters such as the zero-frequency resistivity,the polarizability,the relaxation time,and the frequency correlation coefficient.Moreover,using a least square technique,a complex resistivity“inversion”algorithm is written.The comparison of the initial model parameters and those obtained after inversion is used to verify the stability and accuracy of such approach.The method is finally applied to primary-structure coal considered as the experimental sample for complex resistivity measurements.
基金supported by the National Natural Science Foundation of China(Nos.22171223,22179107,22077099,and 21807087)the Technology Innovation Leading Program of Shaanxi(No.2020TG−031)+2 种基金the Shaanxi Provincial Natural Science Fund Project(No.2018JQ2061)the Xi’an City Science and Technology Project(Nos.2020KJRC011 and 2019218214GXRC018CG019−GXYD18.4)the Outstanding Youth Science Fund of Xi’an University of Science and Technology(No.2018YQ3-14).
文摘Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in considering of the attractive optical properties.In this work,we present a CDs based fluorescent sensor from polyvinylpyrrolidone,citric acid,and methionine as precursors by hydrothermal approach.The selective quantifying of Fe^(3+)and ascorbic acid(AA)are based on the fluorescent on-off-on process,in which the fluorescent quenching is induced by the coordination of the Fe^(3+)on the surface of the CDs,while the fluorescence recovery is mainly attributed to redox reaction between Fe^(3+)and AA,breaking the coordination and bringing the fluorescence back.Inspired by the good water solubility and biocompatibility,significant photostability,superior photobleaching resistance as well as high selectivity,sensitivity,and interference immunity,which are constructed mainly from the N,S-doping and methionine surface functionalization,the CDs have not only been employed as fluorescence ink in multiple anticounterfeiting printing and confidential document writing or transmitting,but also been developed as promising fluorescence sensors in solution and solid by CDs doped test strips and hydrogels for effectively monitoring and removing of Fe^(3+)and AA in environmental aqueous solution.The CDs have been also implemented as effective diagnostic candidates for imaging and tracking of Fe^(3+)and AA in living cells,accelerating the understanding of their function and importance in related biological processes for the prevention and treatment specific diseases.
基金This work is supported by the Aeronautical Science Foundation of China(No.2018ZF53065)the Key Project of Shaanxi Provincial Natural Science Foundation(No.2021JZ-09)+1 种基金the National Undergraduate Training Program for Innovation and Entrepreneurship(No.201910699113)the Shaanxi Province Science Foundation for Youths(No.2023-JC-QN-0146).
文摘Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent years.However,the current construction methods are complicated and resulting PLs possess high viscosity values,which cannot meet the requirements of practical industrial applications.Herein,we demonstrate a generalizable and simple strategy to prepare type III PLs with low viscosity based on the rule of“like dissolves like”.Specifically,the monoglycidyl ether terminated polydimethylsiloxane(denoted by E-PDMS)is attached to the surface of Universitetet i Oslo(UiO)-66-NH_(2)via covalent linkage,constructing the pore generator(UiO-66-NH_(2)-E-PDMS,denoted by P-UiO-66).Then,P-UiO-66 is dispersed into different types and amounts of sterically hindered solvents(PDMS400 or PDMS6000),obtaining a series of type III PLs(denoted by P-UiO-66-PLs)with permanent cavities and low viscosities.The gas sorption-desorption test shows that P-UiO-66-PLs have an enormous potential for CO_(2)/N_(2) selective separation.Besides,the porosity of P-UiO-66-PLs and the CO_(2)sorption mechanism are demonstrated by molecular simulation.Furthermore,the generality of the synthesis strategy is confirmed by the successful construction of PLs using two other amino-metal-organic frameworks(MOFs)(MIL-53(Al)-NH_(2)and MIL-88B(Fe)-NH_(2)).Importantly,it’s worth noting that the strategy based on the rule of“like dissolves like”sheds light on the preparation of other types of PLs for task-specific applications.
基金supported by the National Natural Science Foundation of China(No.41290253)
文摘Here,we describe a new primitive Erinaceidae species,Oligoechinus lanzhouensis n.gen.n.sp.,based on a specimen from late Oligocene strata of the Lanzhou Basin,Gansu Province.Its characteristics are as follows:the M1 width is longer than the length,the metastyle extends far disto-labially,the posterior margin has strong curve and a distinct metaconule that is connected to the protocone by a postprotocrista is located in the centre of the tooth.The posterior arm of the metaconule is poorly developed.In the P4,the pterion of the metastyle is less developed and the metacone is carinate.In addition,O.lanzhouensis has a premolar larger than the canine tooth(P2>C)and P3 had no molarisation,characters also possessed by Erinaceus.Overall,O.lanzhouensis was similar to Mioechinus based on architectural tooth features,demonstrating a closed genetic relationship.Fossil Erinaceidae are relatively rare before the Miocene.The discovery of O.lanzhouensis provides an important insight into the origin of Mioechinus in China and the early evolution of the Erinaceidae.Our analysis shows that a relatively recent ancestor of Mioechinus had probably existed in the early Oligocene and that O.Lanzhouensis was likely an ancestral type of Mioechinus gobiensis,and its systematic position should be located at a transitional position between Amphechinus and Mioechinus.
文摘In order to suppress the surface wave in three-component seismic exploration, according to the polarization characteristics of body wave and surface wave, a time-frequency domain polarization filtering method based on wavelet transform was studied. A covariance matrix was constructed in the time-frequency domain for the three-component seismic data, measured the polarization parameters of seismic waves. Combining the corresponding eigenvalues and eigenvectors of the matrix, the elliptic rate and elevation angle were used as constraints, and the polarization filter function was built to separate the surface waves. The separated surface waves were inversely transformed and then were adaptively subtracted from the original records. After the polarization filtering suppressed the surface wave, the signal-to-noise ratio of the converted wave was effectively improved. It laid a good foundation for the next seismic data processing and seismic exploration development. The actual data processing results show that the method can effectively extract surface waves from three-component seismic records and avoid the interference of surface waves on seismic signals.
文摘The material composition of geological samples is very complicated. Generally, the method for accurately determining trace elements in geological samples needs to digest the solid samples into liquid state, which is convenient for inductively coupled plasma mass spectrometry. The previous digestion method takes a long time and the operation process is complicated. The Ultra CLAVE microwave digestion instrument was used to digest the geological samples. The types and dosages of the acid used for digestion and the optimal conditions for instrumental testing were published. The results show that this method has short processing time, small data error, safer operation and good digestion effect. This method is suitable for geological sample analysis.
基金This work was supported by the National Natural Science Foundation of China(No.51503169)the Project of Excellent Youth Scientific Research Foundation of Xi’an University of Science and Technology,China(No.2019YQ2-10).
文摘A facile hydrothermal strategy is adopted to synthesize the composite of NiCo-layered double hydroxide(NiCo-LDH)with biomass carbon as substrate for supercapacitor electrodes.The prepared NiCo@BC was characterized by means of X-ray diffraction(XRD),scanning electronic microscopy(SEM),Fourier transform infrared spectroscopy(FTIR)and Raman spectroscopy,and electrochemical tests.The SEM images demonstrated that numerous NiCo-LDH nanosheets directly grew on the surface of biomass carbon uniformly.Electrochemical tests indicated that the NiCo@BC electrode exhibited good capacitive behavior with a specific capacitance of 606.4 F/g at the current density of 0.5 A/g.In addition,the composite electrode showed excellent cyclic stability of 87.1%even after 1000 cycles.These results manifest that NiCo@BC nanocomposite is a promising candidate for the electrode material for future supercapacitor practical applications.
基金This work was supported by the National Natural Science Foundation of China(No.51772181)the Fundamental Research Funds for the Central Universities(No.2019TS006)+1 种基金the Natural Science Basic Research Plan of Shaanxi Province(No.2019JLP-12)Shaanxi Sanqin Scholars Innovation Team.
文摘The development of compressible supercapacitors strongly relies on the design of electrode materials combining superior compressibility,high conductivity with the stable electrochemical cycling performance.In this work,we report a facile yet scalable strategy to construct a highly compressible supercapacitor by integrating the current collector,active materials and the separator into one device.We use the highly compressive melamine foam(MF)as scaffold and the Ti_(3)C_(2)T_(x)nanosheets as the active materials.Filling the few-layer Ti_(3)C_(2)T_(x)nanosheets into the skeleton of MF by capillary force followed by freeze-drying yields the MF/Ti_(3)C_(2)T_(x)composite with superior structural integrity that can be compressed at a large strain of 50%for 100 cycles.The electrochemical performances of the all-in-one supercapacitor were systematically investigated under diverse compression strains.The improved conductivity and reduced ion diffusion length allow the all-in-one supercapacitor to exhibit fast ion and electron kinetics even at high strain of 60%,delivering a maximal volumetric specific energy of 0.37 mWh∙cm^(-3)at power density of 0.42 mW∙cm^(-3)and extraordinary cycling performance during the 2,500 compression cycles.
