High-pressure research has emerged as a pivotal approach for advancing our understanding and development of optoelectronic materials,which are vital for a wide range of applications,including photovoltaics,light-emitt...High-pressure research has emerged as a pivotal approach for advancing our understanding and development of optoelectronic materials,which are vital for a wide range of applications,including photovoltaics,light-emitting devices,and photodetectors.This review highlights various in situ characterization methods employed in high-pressure research to investigate the optical,electronic,and structural properties of optoelectronic materials.We explore the advances that have been made in techniques such as X-ray diffraction,absorption spectroscopy,nonlinear optics,photoluminescence spectroscopy,Raman spectroscopy,and photoresponse measurement,emphasizing how these methods have enhanced the elucidation of structural transitions,bandgap modulation,performance optimization,and carrier dynamics engineering.These insights underscore the pivotal role of high-pressure techniques in optimizing and tailoring optoelectronic materials for future applications.展开更多
The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based t...The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.展开更多
The advancement of electron microscopy technology has driven the development of electron microscopes that can apply mechanical loading while observing samples,providing a valuable tool for In-Situ mechanical character...The advancement of electron microscopy technology has driven the development of electron microscopes that can apply mechanical loading while observing samples,providing a valuable tool for In-Situ mechanical characterization of materials.In response to the need to characterize the evolution of the mechanical behavior of structural materials,such as aerospace materials,in real cryogenic service environments,and to provide an experimental basis for improving their macroscopic cryogenic mechanical properties,the advancement of In-Situ characterization techniques capable of offering both cryogenic environments and mechanical loading has become imperative.There have been scholars using this technique to carry out cryogenic mechanical In-Situ studies of related materials,with experimental studies dominating in general,and a few reviews of mechanical characterization techniques mentioning cryogenic temperatures.In order to make it easier to conduct research using such characterization techniques and to further promote the development of related characterization techniques,this review compiles the previous work and summarizes the electron microscope-based In-Situ characterization techniques for cryogenic micro-and nanomechanics.These techniques primarily include transmission electron microscopy-based cryogenic tensile and indentation methods,as well as scanning electron microscopy-based cryogenic tensile,indentation,compression,and bending methods.Furthermore,the review outlines the prospective future development of In-Situ characterization techniques for cryogenic micro-and nanomechanics.展开更多
Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the preven...Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the prevention and control of LF.Methods Samples of cerebrospinal fluid(CSF),blood,urine,saliva,and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection.Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus.Results LASV was detected in the patient’s CSF,blood,and urine,while all samples from close contacts and the environment tested negative.The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone.The variability in the glycoprotein complex(GPC)among different strains ranged from 3.9%to 15.1%,higher than previously reported for the seven known lineages.Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes,increasing strain diversity and potentially impacting immune response.Conclusion The case was confirmed through nucleotide detection,with no evidence of secondary transmission or viral spread.The LASV strain identified belongs to lineage IV,with broader GPC variability than previously reported.Mutations in the immune-related sites of GPC may affect immune responses,necessitating heightened vigilance regarding the virus.展开更多
With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,off...With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,offers a promising avenue for researchers.However,the question of how to significantly enhance the performance of catalysts has gradually drawn the attention of scholars.Defect engineering,a commonly employed and effective approach to improve catalyst activity,has become a significant research focus in the catalysis field in recent years.Nonmetal vacancies have received extensive attention due to their simple form.Consequently,exploration of metal vacancies has remained stagnant for a considerable period,resulting in a scarcity of comprehensive reviews on this topic.Therefore,based on the latest research findings,this paper summarizes and consolidates the construction strategies for metal vacancies,characterization techniques,and their roles in typical energy and environmental catalytic reactions.Additionally,it outlines potential challenges in the future,aiming to provide valuable references for researchers interested in investigating metal vacancies.展开更多
2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(...2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.展开更多
A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]py...A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.展开更多
The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monit...The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.展开更多
Aeromonas spp.are commonly found in spoilage of chilled meat.Aeromonas salmonicida NCM 29 and A.salmonicida NCM 57 have been discovered the spoilage heterogeneity in degrading myofibrillar protein.In this study,the tw...Aeromonas spp.are commonly found in spoilage of chilled meat.Aeromonas salmonicida NCM 29 and A.salmonicida NCM 57 have been discovered the spoilage heterogeneity in degrading myofibrillar protein.In this study,the two strains were tested to uncover the discrepancy of meat spoilage in collagen-rich chilled meat and extracted collagen.The results revealed that chicken claws,riched in collagen,inoculated with NCM 29 showed higher values of total viable counts(TVC),total volatile basic nitrogen(TVB-N),pH,adhered cells,trichloroacetic acid(TCA)-soluble peptides,and protease activity compared to those inoculated with NCM 57.Furthermore,NCM 29 generated higher quantity of volatile organic compounds related to meat spoilage.The collagenase((hemagglutinin protease(Hap))secreted by NCM 29 has been identified as the key factor responsible for the observed discrepancies in spoilage,which gradually degraded collagen into peptides and hydroxyproline.The capacity of Hap to degrade type Ⅰ collagen in vitro indicated that it has apparent proteolytic activity,which could reduce the average particle size and alter secondary structure of collagen.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)further confirmed the degradation of theβ-chain in collagen.These findings not only provide a theoretical basis for in-depth investigation of the meat spoilage mechanisms of Aeromonas spp.,but also encourage us to take measures to avoid the spoilage of related bacteria such as Aeromonas spp.during the preservation process.展开更多
This review article provides a comprehensive examination of the most recent advances in research on nanoglasses,including the methods used to create these materials,their characteristics,and their diverse range of use...This review article provides a comprehensive examination of the most recent advances in research on nanoglasses,including the methods used to create these materials,their characteristics,and their diverse range of uses.An overview of the current trends in nanoglass research connects them to the Sustainable Development Goals,highlighting the current relevance of this topic.The process of manufacturing nanoglasses is explained in depth,highlighting advanced approaches such as inert gas condensation and severe plastic deformation,among other techniques.The prime focus of this review is on analyzing the various dimensions of nanoglass materials,including their structural dynamics and electrical configurations,and how these features contribute to their exceptional thermal stability and mechanical strength.The magnetic characteristics of nanoglasses are examined,highlighting their potential for driving innovation across multiple industries.The primary emphasis is on the biological usefulness of nanoglasses,specifically examining their bioactivity and interaction with biological components,and emphasizing their growing use in nanoscale biomedical applications.With regard to the practical applications of nanoglasses,there are specific discussions of their contributions to biological evaluation,wound healing,catalysis,and environmental sustainability.There is an emphasis on the durability and resistance of nanoglasses in these contexts.The comprehensive overview of nanoglasses provided in this article highlights their significance as revolutionary materials in fields of science and technology.The potential of nanoglasses to contribute to a future that is more sustainable and health oriented is indicated.The article ends by discussing the future directions for nanoglass research and looks forward to the promising possibilities for further investigation and innovation.展开更多
Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can re...Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can react in various chemical reactions and serve as a raw material in various processes to obtain multiple products.These characteristics make lignin suitable for synthesizing products from natural raw materials,replacing fossil ones.Due to a high aromatic variety and complex structural arrangement,lignin isolation and fractionation are still challenging.The aim and novelty of this work was the modification of severity and enzymatic hydrolysis proce-dure on an industrial pre-treatment to improve by-products of birch processing as a raw material for the potential production of different products.Lignin from birch wood enzymatic hydrolysis was obtained and marked accord-ingly:HS(high severity),MS(medium severity),and LS(low severity)lignin.Samples were characterized by ash content,analytical pyrolysis,solubility,and viscosity.HS lignin was characterized by a relatively high carbohy-drate content(16%)and lower lignin content(77%).Meanwhile,LS lignin showed increased lignin content(83%)and reduced carbohydrate content(9%).It can be concluded that the delignification process greatly influ-ences the properties of the obtained lignin.HS lignin resulted in a lower polydispersity index(PDI)and more condensed structure,while LS lignin showed a higher PDI but a lower content of carbohydrates.Therefore,look-ing for a golden middle way is necessary whilefinding the conditions according to the usefield.展开更多
Sea buckthorn(Hippophae rhamnoides L.)is a natural homologous substance of medicine and food.Polysaccharide,as one of its primary active components,has very superior biological activity and can be used as a dietary su...Sea buckthorn(Hippophae rhamnoides L.)is a natural homologous substance of medicine and food.Polysaccharide,as one of its primary active components,has very superior biological activity and can be used as a dietary supplement for functional foods,with good commercial prospects.Although initial progress has been made in the study of sea buckthorn polysaccharides,related studies have been fragmented and lacked systematic and generalization.This manuscript presents a critical analysis and systematic summary of the extraction and purification methods,structural characterization and physicochemical properties,biological activity and potential mechanisms,and structure-activity relationships of sea buckthorn polysaccharides.Accumulating evidence has indicated that sea buckthorn polysaccharides,which were widely prepared by water extraction and column chromatography purifications,exhibited exhibit superior biological activities in vitro and in vivo,including antioxidant,immunomodulatory,anti-inflammatory,hepatorenal protective,antibacterial,antiviral,and prebiotic activities.After analysis,it was concluded that there is a correlation between the relevant activities of sea buckthorn polysaccharides and that the structure of sea buckthorn polysaccharides has a great influence on their biological activity.We reviewed the challenges and limitations of sea buckthorn polysaccharides,summarized the critical aspects,and provided suggestions for potential breakthroughs in the research and application of sea buckthorn polysaccharide.展开更多
High-purity SiO_(2)nanoparticles(SNPs)play a crucial role in various electronic applications,such as semiconductors,solar cells,optical fibers,lenses,and insulating layers,given their purity and particle size,which si...High-purity SiO_(2)nanoparticles(SNPs)play a crucial role in various electronic applications,such as semiconductors,solar cells,optical fibers,lenses,and insulating layers,given their purity and particle size,which significantly impact device efficiency.This study fo-cuses on the synthesis and characterization of pure SNPs through the chemical etching of greater club rush.White powder SNPs were pre-pared using HCl etching,and their thermal behaviors were analyzed via thermogravimetric analysis/differential scanning calorimetry.Structural properties were investigated using X-ray fluorescence,scanning electron microscopy,and transmission electron microscopy.X-ray absorption near-edge structure was employed to assess the oxidation state of the SNPs.The morphology of the SNPs after the first etching was amorphous,with sizes ranging from 50 to 100 nm,which increased to 50-200 nm after the second etching.Despite this size variation,the SNPs maintained a high purity level of 99.8wt%SiO_(2),comparable with industry standards.Notably,the second etching with 0.1-M HCl significantly enhanced the purity level,achieving 99.8wt%SiO_(2)mass.Furthermore,HCl etching facilitated the formation of SiO_(2)in the Si^(4+)oxidation state,akin to industrial SNPs.These findings underscore the critical role of HCl etching in synthesizing high-purity SNPs,with potential applications in advanced electronic devices.展开更多
High molecular weight poly(1,4-butylene 2,5-furandicarboxylate-co-isosorbide 2,5-furandicarboxylate)copolyesters(PBSIF-x)were synthesized via melt-polycondensation of 2,5-furandicarboxylic acid(FDCA),with varying rati...High molecular weight poly(1,4-butylene 2,5-furandicarboxylate-co-isosorbide 2,5-furandicarboxylate)copolyesters(PBSIF-x)were synthesized via melt-polycondensation of 2,5-furandicarboxylic acid(FDCA),with varying ratios of isosorbide(ISB)and 1,4-butylene glycol(BDO)catalyzed by antimony trioxide(Sb_(2)O_(3)).The PBSIF-x structures were investigated using FTIR and~1H NMR,while the GPC analysis exhibited the copolyesters molecular weights with number average molecular mass(M_n)in the range of 11079-15153 g/mol.The DSC results show that PBSIF-x copolyesters have a single glass-transition temperature(T_(g))(77.45-110.96℃),increasing with the increase in ISB content,while TGA analysis demonstrates excellent thermal stability up to 320℃.From the thermal result,properties of PBSIF-x copolyesters are found to be within the interval of their parent homologues poly(butylene 2,5-furandicarboxylate)(PBF)and poly(isosorbide 2,5-furandicarboxylate)(PIF),which confirms the aromatic/aliphatic blending within the polymer matrix for enhanced polymer stability and performance.展开更多
Cashew processing in Côte d’Ivoire focuses only on the cashew nut, to the detriment of the apple. Only a very small proportion of the apple is processed into juice. The aim of this work is to enhance the value o...Cashew processing in Côte d’Ivoire focuses only on the cashew nut, to the detriment of the apple. Only a very small proportion of the apple is processed into juice. The aim of this work is to enhance the value of cashew apples by transforming them into jam. Specifically, the aim was first to characterize the sensory properties of cashew apple jam formulations using baobab powder as a source of pectin and then to optimise the formulations. A Box-Behken design with pH, Sugar, and Baobab as factors was used to model and characterize the jam sensory descriptors, and a multivariate analysis with SensomineR was used to characterize the jam formulations. The desirability function was used to optimise the formulations. The results show globally significant regressions at the 0.05 threshold for the sensory descriptors Gelling, Brilliance, Smell, Sweetness, and (-)Astringency, with the exception of (-)Salinity. The R2 coefficients are greater than 80%. The factors studied could have effects on the sensory descriptors of cashew jam formulations. The Baobab had the main effect on the gelling, smell, and astringency of the jams. Brilliance depended on the added sugar. A product effect (p < 0.001) was observed for the descriptors Smell, Gelling, Brilliance, and Sweetness, as these allowed the panelists to find differences between the formulations. Optimum jam formulation can be achieved with 51.56% sugar and 2.12% Baobab at a pH of 3.15. Cashew apple jam using Baobab offers opportunities to add value to apples that have long been abandoned in the field. It would be important to find conditions for prolonged storage of this jam.展开更多
Panax notoginseng is a traditional Chinese medicine containing various constituents,including the saponins,polysaccharides,polyacetylenes,amino acids,etc.It has beneficial functions,such as the anti-inflammatory,antit...Panax notoginseng is a traditional Chinese medicine containing various constituents,including the saponins,polysaccharides,polyacetylenes,amino acids,etc.It has beneficial functions,such as the anti-inflammatory,antitumor,hepatoprotective,and anti-aging effects.Among these,P.notoginseng polysaccharides(PNPs)have been exploited because of their extensive pharmacological effects,being ranked as one of the current research hotspots,especially for the functional foods and medical practice.In this review,the literature related to PNPs in the past 20 years was surveyed and analyzed using both the China National Knowledge Infrastructure(CNKI)and Web of Science(WOS)databases.The visualization diagram shows that current studies on PNPs mainly focus on the antioxidant and immunomodulatory activities and structural characterization.In addition,the extraction,separation,purification,chemical analysis,structural characteristics,bioactivities,and applications of PNPs are outlined,in detail,aimed to provide valuable information for the further study,development,and utilization regarding PNPs.展开更多
The characterization and clustering of rock discontinuity sets are a crucial and challenging task in rock mechanics and geotechnical engineering.Over the past few decades,the clustering of discontinuity sets has under...The characterization and clustering of rock discontinuity sets are a crucial and challenging task in rock mechanics and geotechnical engineering.Over the past few decades,the clustering of discontinuity sets has undergone rapid and remarkable development.However,there is no relevant literature summarizing these achievements,and this paper attempts to elaborate on the current status and prospects in this field.Specifically,this review aims to discuss the development process of clustering methods for discontinuity sets and the state-of-the-art relevant algorithms.First,we introduce the importance of discontinuity clustering analysis and follow the comprehensive characterization approaches of discontinuity data.A bibliometric analysis is subsequently conducted to clarify the current status and development characteristics of the clustering of discontinuity sets.The methods for the clustering analysis of rock discontinuities are reviewed in terms of single-and multi-parameter clustering methods.Single-parameter methods can be classified into empirical judgment methods,dynamic clustering methods,relative static clustering methods,and static clustering methods,reflecting the continuous optimization and improvement of clustering algorithms.Moreover,this paper compares the current mainstream of single-parameter clustering methods with multi-parameter clustering methods.It is emphasized that the current single-parameter clustering methods have reached their performance limits,with little room for improvement,and that there is a need to extend the study of multi-parameter clustering methods.Finally,several suggestions are offered for future research on the clustering of discontinuity sets.展开更多
Opening-mode fractures play a crucial role in shale reservoirs,as they serve as flow channels and provide storage space for hydrocarbons.The shale reservoirs in the Permian Lucaogou Formation of the Junggar Basin,NW C...Opening-mode fractures play a crucial role in shale reservoirs,as they serve as flow channels and provide storage space for hydrocarbons.The shale reservoirs in the Permian Lucaogou Formation of the Junggar Basin,NW China,record multi-stage tectonic and diagenetic processes that created multi-stage natural fractures,thereby contributing to the oil content differentiation within the formation.Effective identification and characterization of natural fractures is vital for the efficient recovery of shale oil in the Jimsar Sag.We combine outcrop observations,drill core analyses,thin section examinations,and well log analyses to determine the characteristics of fractures in the shale reservoirs and their modes of development.We also establish multi-parameter evaluation index criteria and an evaluation system for fractures using statistical analyses.The shale reservoirs of the Lucaogou Formation in the Jimsar Sag host three main types of fracture:tectonic fractures,diagenetic fractures,and overpressure fractures.Conventional well logging,imaging logging,and core observations demonstrate that the fractured shale reservoir section has gamma-ray counts(GR)of>75 API,shallow laterolog resistivities of<80Ω·m,neutron densities of<2.40 g/cm3,neutron porosities of>27%,and interval transit times of>23.77μs/m,fracture density exceeding 3 fractures/m,and average porosity ranging from 0.2%to 0.3%in the lower sweet spots.The lower sweet spot(P2l12)of the Lucaogou Formation exhibits the highest degree of fracture development.Our detailed characterization reveals high fracture permeabilities and porosities in the upper and lower sweet spots(P2l22 and P2l12),with higher values in the latter.In addition,we present a novel rose diagram method to represent various fracture parameters.The best-developed tectonic fractures in the Lucaogou Formation strike ENE-WSW,have an average linear density of 1.65 fractures/m,an average aperture of 0.25 mm,an average length of 8.7 cm,and the highest proportion of unfilled fractures.Our study shows that a combination of field observations,drill core analyses,microscopic observations,and well logging provides a solid foundation for investigating the mechanisms of fracture formation in shale reservoirs.展开更多
In the Republic of Benin,as in many other West African countries,urban areas have experienced rapid popula-tion growth in recent years.This situation has led to an increasing demand for sanitation facilities,necessita...In the Republic of Benin,as in many other West African countries,urban areas have experienced rapid popula-tion growth in recent years.This situation has led to an increasing demand for sanitation facilities,necessitating regular emptying of these systems.In a bid to reduce health risks and protect the surrounding natural environment,the manage-ment of the by-products from these systems has become a significant concern for decision-makers at various levels.This study aims to characterize fecal sludge at the Abomey-Calavi treatment station and suggest a mixed biological treatment approach.Fifteen sewage sludge samples were collected in 1,500 ml plastic bottles from Adjagbo’s Sewage Treatment Station,operated by SGDS-SA,a Waste Management and Sanitation company.Physico-chemical parameters were de-termined using spectrophotometric analysis.Colonies were enumerated using membrane filtration and inoculation.Cor-relation analysis was performed on sewage sludge samples.The main results indicate an alkaline character(pH>7)and a high organic pollutant load in the fecal sludge,with average concentrations of Chemical Oxygen Demand(COD)and Biochemical Oxygen Demand over 5 days(BOD_(5))at 18,730 mg O_(2).L^(-1)and 6,612 mg O_(2).L^(-1),respectively.The COD/BOD_(5) ratio of 2.83 suggests that the material is partially biodegradable.Furthermore,the nutrients exhibited high con-centrations of nitrates,with an average value of 4,786 mg.L^(-1),while nitrites,ammoniacal nitrogen,and orthophosphates had average concentrations of 22.48 mg.L^(-1),119.74 mg.L^(-1),and 239.0 mg.L^(-1),respectively.This study characterized fe-cal sludge at the Abomey-Calavi treatment station and suggests a mixed biological treatment approach.展开更多
With the development of wireless communication,the fifth generation mobile communication technology(5G)has emerged as a hot topic in highspeed railway communication system and has moved towards industrial application....With the development of wireless communication,the fifth generation mobile communication technology(5G)has emerged as a hot topic in highspeed railway communication system and has moved towards industrial application.Investigating the radio propagation characteristics in 5G high-speed train(HST)scenarios is essential for enhancing wireless coverage and overall system performance.We propose a novel 5G passive sounding scheme to extract channel impulse responses(CIRs)using channel state information reference signals(CSI-RS)from the target 5G base station(BS).Detailed procedures for timefrequency synchronization,CSI-RS detection and extraction are presented through simulations.Through the laboratory work involving absolute power calibration,phase coherence calibration and power delay profile(PDP)validation,we validate the accuracy and performance of the developed platform.Furthermore,a measurement campaign was conducted in HST scenarios encompassing both residential and undeveloped areas.The path loss(PL)model and the channel characteristics including stationarity interval(SI),multipath components(MPCs),shadow fading(SF),Rician K-factor,root mean square(RMS)delay spread and received correlation coefficients are analyzed and fitted.The estimated channel characteristics and the statistical model presented in this paper will contribute to the research on HST radio propagation and the development of 5G railway communication systems.展开更多
基金supported by the National Nature Science Foundation of China(NSFC)(Grant Nos.22275004,62274040,and 62304046)the Shanghai Science and Technology Committee(Grant No.22JC1410300)+2 种基金the Shanghai Key Laboratory of Novel Extreme Condition Materials(Grant No.22dz2260800)the National Key Research and Development Program of China(Grant No.2022YFE0137400)the Shanghai Science and Technology Innovationaction Plan(Grant No.24DZ3001200).
文摘High-pressure research has emerged as a pivotal approach for advancing our understanding and development of optoelectronic materials,which are vital for a wide range of applications,including photovoltaics,light-emitting devices,and photodetectors.This review highlights various in situ characterization methods employed in high-pressure research to investigate the optical,electronic,and structural properties of optoelectronic materials.We explore the advances that have been made in techniques such as X-ray diffraction,absorption spectroscopy,nonlinear optics,photoluminescence spectroscopy,Raman spectroscopy,and photoresponse measurement,emphasizing how these methods have enhanced the elucidation of structural transitions,bandgap modulation,performance optimization,and carrier dynamics engineering.These insights underscore the pivotal role of high-pressure techniques in optimizing and tailoring optoelectronic materials for future applications.
文摘The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.
基金supported by the National Natural Science Foundation of China(52301177)。
文摘The advancement of electron microscopy technology has driven the development of electron microscopes that can apply mechanical loading while observing samples,providing a valuable tool for In-Situ mechanical characterization of materials.In response to the need to characterize the evolution of the mechanical behavior of structural materials,such as aerospace materials,in real cryogenic service environments,and to provide an experimental basis for improving their macroscopic cryogenic mechanical properties,the advancement of In-Situ characterization techniques capable of offering both cryogenic environments and mechanical loading has become imperative.There have been scholars using this technique to carry out cryogenic mechanical In-Situ studies of related materials,with experimental studies dominating in general,and a few reviews of mechanical characterization techniques mentioning cryogenic temperatures.In order to make it easier to conduct research using such characterization techniques and to further promote the development of related characterization techniques,this review compiles the previous work and summarizes the electron microscope-based In-Situ characterization techniques for cryogenic micro-and nanomechanics.These techniques primarily include transmission electron microscopy-based cryogenic tensile and indentation methods,as well as scanning electron microscopy-based cryogenic tensile,indentation,compression,and bending methods.Furthermore,the review outlines the prospective future development of In-Situ characterization techniques for cryogenic micro-and nanomechanics.
基金supported by Public Health Talent Training and Surport Plan(National Administration of Disease Prevention and Control)Research and application of new technology for rapid monitoring and tracing of emergent infectious diseases among entry-exit population(2024YFFK0056)Monitoring,Early warning and Response of Major Infectious Diseases(2022ZDZX0017).
文摘Objective This study reports the first imported case of Lassa fever(LF)in China.Laboratory detection and molecular epidemiological analysis of the Lassa virus(LASV)from this case offer valuable insights for the prevention and control of LF.Methods Samples of cerebrospinal fluid(CSF),blood,urine,saliva,and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection.Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus.Results LASV was detected in the patient’s CSF,blood,and urine,while all samples from close contacts and the environment tested negative.The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone.The variability in the glycoprotein complex(GPC)among different strains ranged from 3.9%to 15.1%,higher than previously reported for the seven known lineages.Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes,increasing strain diversity and potentially impacting immune response.Conclusion The case was confirmed through nucleotide detection,with no evidence of secondary transmission or viral spread.The LASV strain identified belongs to lineage IV,with broader GPC variability than previously reported.Mutations in the immune-related sites of GPC may affect immune responses,necessitating heightened vigilance regarding the virus.
基金financially supported by National Key R&D Program of China(2021YFB3500702)National Natural Science Foundation of China(Nos.21677010 and 51808037)Special fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF21-04).
文摘With the ongoing depletion of fossil fuels,energy and environmental issues have become increasingly critical,necessitating the search for effective solutions.Catalysis,being one of the hallmarks of modern industry,offers a promising avenue for researchers.However,the question of how to significantly enhance the performance of catalysts has gradually drawn the attention of scholars.Defect engineering,a commonly employed and effective approach to improve catalyst activity,has become a significant research focus in the catalysis field in recent years.Nonmetal vacancies have received extensive attention due to their simple form.Consequently,exploration of metal vacancies has remained stagnant for a considerable period,resulting in a scarcity of comprehensive reviews on this topic.Therefore,based on the latest research findings,this paper summarizes and consolidates the construction strategies for metal vacancies,characterization techniques,and their roles in typical energy and environmental catalytic reactions.Additionally,it outlines potential challenges in the future,aiming to provide valuable references for researchers interested in investigating metal vacancies.
文摘2-substituted-1-amino-o-carboranes 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10)(R=CH_(3),1a;R=Ph,1b)were synthesized and the reactions of these compounds with the yttrium dialkyl complex[Y(L)(CH_(2)SiMe3)_(2)](L=[2-(2,5-Me_(2)C_(4)H_(2)N)C_(6)H4NC(Ph)=NDipp]-,Dipp=2,6-iPr_(2)C_(6)H_(3))were investigated.The 1H NMR spectroscopy indicate that the reaction of ytrrium dialkyl complex with one equivalent of 2-R-1-NH_(2)-o-C_(2)B_(10)H_(10) produce the mixture of ytrrium alkyl-amido complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))(CH_(2)SiMe3)](R=CH_(3),2a;R=Ph,2b)and bis(amido)complex[Y(L)(2-R-1-NH-o-C_(2)B_(10)H_(10))_(2)](R=CH_(3),3a;R=Ph,3b).The yttrium bridging imido complex[Y(L)(2-CH_(3)-1-N-o-C_(2)B_(10)H_(10))]_(2)(4a)was obtained by heating the mixture at 55℃for 12 h.Complex 3a was isolated and characterized by treating the yttrium dialkyl complex with two equivalents of 1a.The structures of complexes 3a and 4a were verified by single-crystal Xray diffraction.CCDC:2424136,3a;2424137,4a.
文摘A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.
基金湖南省教育厅基金优秀青年项目(No.22B0482)湖南科技大学博士启动基金(No.E51992 and E51993)资助。
文摘The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.
基金supported by projects funded by grants from the Natural Science Foundation of Jiangsu Province in China(BK20221515)the National Natural Science Foundation of China(32172266).
文摘Aeromonas spp.are commonly found in spoilage of chilled meat.Aeromonas salmonicida NCM 29 and A.salmonicida NCM 57 have been discovered the spoilage heterogeneity in degrading myofibrillar protein.In this study,the two strains were tested to uncover the discrepancy of meat spoilage in collagen-rich chilled meat and extracted collagen.The results revealed that chicken claws,riched in collagen,inoculated with NCM 29 showed higher values of total viable counts(TVC),total volatile basic nitrogen(TVB-N),pH,adhered cells,trichloroacetic acid(TCA)-soluble peptides,and protease activity compared to those inoculated with NCM 57.Furthermore,NCM 29 generated higher quantity of volatile organic compounds related to meat spoilage.The collagenase((hemagglutinin protease(Hap))secreted by NCM 29 has been identified as the key factor responsible for the observed discrepancies in spoilage,which gradually degraded collagen into peptides and hydroxyproline.The capacity of Hap to degrade type Ⅰ collagen in vitro indicated that it has apparent proteolytic activity,which could reduce the average particle size and alter secondary structure of collagen.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)further confirmed the degradation of theβ-chain in collagen.These findings not only provide a theoretical basis for in-depth investigation of the meat spoilage mechanisms of Aeromonas spp.,but also encourage us to take measures to avoid the spoilage of related bacteria such as Aeromonas spp.during the preservation process.
基金M.A.F.acknowledges the financing support by Universidad Nacional del Sur(Grant No.PGI 24/Q112 and Grant No.PICT 2021-I-A-00288)Agencia Nacional de Promoción Científica y Tecnológica(ANPCyT)(Grant No.PIP 2021-2023 GI 11220200100317CO).
文摘This review article provides a comprehensive examination of the most recent advances in research on nanoglasses,including the methods used to create these materials,their characteristics,and their diverse range of uses.An overview of the current trends in nanoglass research connects them to the Sustainable Development Goals,highlighting the current relevance of this topic.The process of manufacturing nanoglasses is explained in depth,highlighting advanced approaches such as inert gas condensation and severe plastic deformation,among other techniques.The prime focus of this review is on analyzing the various dimensions of nanoglass materials,including their structural dynamics and electrical configurations,and how these features contribute to their exceptional thermal stability and mechanical strength.The magnetic characteristics of nanoglasses are examined,highlighting their potential for driving innovation across multiple industries.The primary emphasis is on the biological usefulness of nanoglasses,specifically examining their bioactivity and interaction with biological components,and emphasizing their growing use in nanoscale biomedical applications.With regard to the practical applications of nanoglasses,there are specific discussions of their contributions to biological evaluation,wound healing,catalysis,and environmental sustainability.There is an emphasis on the durability and resistance of nanoglasses in these contexts.The comprehensive overview of nanoglasses provided in this article highlights their significance as revolutionary materials in fields of science and technology.The potential of nanoglasses to contribute to a future that is more sustainable and health oriented is indicated.The article ends by discussing the future directions for nanoglass research and looks forward to the promising possibilities for further investigation and innovation.
文摘Research-based on lignin as a bioproduct has grown due to its high availability,reactivity,physicochemical sta-bility,and abundance of different aromatic units.Lignin consists of various functional groups,which can react in various chemical reactions and serve as a raw material in various processes to obtain multiple products.These characteristics make lignin suitable for synthesizing products from natural raw materials,replacing fossil ones.Due to a high aromatic variety and complex structural arrangement,lignin isolation and fractionation are still challenging.The aim and novelty of this work was the modification of severity and enzymatic hydrolysis proce-dure on an industrial pre-treatment to improve by-products of birch processing as a raw material for the potential production of different products.Lignin from birch wood enzymatic hydrolysis was obtained and marked accord-ingly:HS(high severity),MS(medium severity),and LS(low severity)lignin.Samples were characterized by ash content,analytical pyrolysis,solubility,and viscosity.HS lignin was characterized by a relatively high carbohy-drate content(16%)and lower lignin content(77%).Meanwhile,LS lignin showed increased lignin content(83%)and reduced carbohydrate content(9%).It can be concluded that the delignification process greatly influ-ences the properties of the obtained lignin.HS lignin resulted in a lower polydispersity index(PDI)and more condensed structure,while LS lignin showed a higher PDI but a lower content of carbohydrates.Therefore,look-ing for a golden middle way is necessary whilefinding the conditions according to the usefield.
基金supported by the National Natural Science Foundation of China(32201994)。
文摘Sea buckthorn(Hippophae rhamnoides L.)is a natural homologous substance of medicine and food.Polysaccharide,as one of its primary active components,has very superior biological activity and can be used as a dietary supplement for functional foods,with good commercial prospects.Although initial progress has been made in the study of sea buckthorn polysaccharides,related studies have been fragmented and lacked systematic and generalization.This manuscript presents a critical analysis and systematic summary of the extraction and purification methods,structural characterization and physicochemical properties,biological activity and potential mechanisms,and structure-activity relationships of sea buckthorn polysaccharides.Accumulating evidence has indicated that sea buckthorn polysaccharides,which were widely prepared by water extraction and column chromatography purifications,exhibited exhibit superior biological activities in vitro and in vivo,including antioxidant,immunomodulatory,anti-inflammatory,hepatorenal protective,antibacterial,antiviral,and prebiotic activities.After analysis,it was concluded that there is a correlation between the relevant activities of sea buckthorn polysaccharides and that the structure of sea buckthorn polysaccharides has a great influence on their biological activity.We reviewed the challenges and limitations of sea buckthorn polysaccharides,summarized the critical aspects,and provided suggestions for potential breakthroughs in the research and application of sea buckthorn polysaccharide.
基金supported by the Suranaree University of Technology(SUT)Center of Excellence(CoE)on Advanced Functional Materials(AFM),School of Physics,Suranaree University of Technology,Nakhon Ratchasima,Thailand,the External Grants and Scholarships for Graduate Students,Suranaree University of Technology,Nakhon Ratchasima,Thailand,and the Research Network on Nanotechnology(RNN),Suranaree University of Technology,Nakhon Ratchasima,Thailand.
文摘High-purity SiO_(2)nanoparticles(SNPs)play a crucial role in various electronic applications,such as semiconductors,solar cells,optical fibers,lenses,and insulating layers,given their purity and particle size,which significantly impact device efficiency.This study fo-cuses on the synthesis and characterization of pure SNPs through the chemical etching of greater club rush.White powder SNPs were pre-pared using HCl etching,and their thermal behaviors were analyzed via thermogravimetric analysis/differential scanning calorimetry.Structural properties were investigated using X-ray fluorescence,scanning electron microscopy,and transmission electron microscopy.X-ray absorption near-edge structure was employed to assess the oxidation state of the SNPs.The morphology of the SNPs after the first etching was amorphous,with sizes ranging from 50 to 100 nm,which increased to 50-200 nm after the second etching.Despite this size variation,the SNPs maintained a high purity level of 99.8wt%SiO_(2),comparable with industry standards.Notably,the second etching with 0.1-M HCl significantly enhanced the purity level,achieving 99.8wt%SiO_(2)mass.Furthermore,HCl etching facilitated the formation of SiO_(2)in the Si^(4+)oxidation state,akin to industrial SNPs.These findings underscore the critical role of HCl etching in synthesizing high-purity SNPs,with potential applications in advanced electronic devices.
基金Funded by the Program(BG2021)of High-end Foreign Experts of The State Administration of Foreign Experts Affairs(SAFEA)the Young Talent Project of Hubei Provincial Department of Education,China(No.Q20201108)。
文摘High molecular weight poly(1,4-butylene 2,5-furandicarboxylate-co-isosorbide 2,5-furandicarboxylate)copolyesters(PBSIF-x)were synthesized via melt-polycondensation of 2,5-furandicarboxylic acid(FDCA),with varying ratios of isosorbide(ISB)and 1,4-butylene glycol(BDO)catalyzed by antimony trioxide(Sb_(2)O_(3)).The PBSIF-x structures were investigated using FTIR and~1H NMR,while the GPC analysis exhibited the copolyesters molecular weights with number average molecular mass(M_n)in the range of 11079-15153 g/mol.The DSC results show that PBSIF-x copolyesters have a single glass-transition temperature(T_(g))(77.45-110.96℃),increasing with the increase in ISB content,while TGA analysis demonstrates excellent thermal stability up to 320℃.From the thermal result,properties of PBSIF-x copolyesters are found to be within the interval of their parent homologues poly(butylene 2,5-furandicarboxylate)(PBF)and poly(isosorbide 2,5-furandicarboxylate)(PIF),which confirms the aromatic/aliphatic blending within the polymer matrix for enhanced polymer stability and performance.
文摘Cashew processing in Côte d’Ivoire focuses only on the cashew nut, to the detriment of the apple. Only a very small proportion of the apple is processed into juice. The aim of this work is to enhance the value of cashew apples by transforming them into jam. Specifically, the aim was first to characterize the sensory properties of cashew apple jam formulations using baobab powder as a source of pectin and then to optimise the formulations. A Box-Behken design with pH, Sugar, and Baobab as factors was used to model and characterize the jam sensory descriptors, and a multivariate analysis with SensomineR was used to characterize the jam formulations. The desirability function was used to optimise the formulations. The results show globally significant regressions at the 0.05 threshold for the sensory descriptors Gelling, Brilliance, Smell, Sweetness, and (-)Astringency, with the exception of (-)Salinity. The R2 coefficients are greater than 80%. The factors studied could have effects on the sensory descriptors of cashew jam formulations. The Baobab had the main effect on the gelling, smell, and astringency of the jams. Brilliance depended on the added sugar. A product effect (p < 0.001) was observed for the descriptors Smell, Gelling, Brilliance, and Sweetness, as these allowed the panelists to find differences between the formulations. Optimum jam formulation can be achieved with 51.56% sugar and 2.12% Baobab at a pH of 3.15. Cashew apple jam using Baobab offers opportunities to add value to apples that have long been abandoned in the field. It would be important to find conditions for prolonged storage of this jam.
基金supported by the National Key R&D Program of China(2022YFC3501805)the Science and Technology Program of Tianjin in China(23ZYJDSS00030)+2 种基金the National Natural Science Foundation of China(82374030)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(2021KJ127)Tianjin Outstanding Youth Fund(23JCJQJC00030).
文摘Panax notoginseng is a traditional Chinese medicine containing various constituents,including the saponins,polysaccharides,polyacetylenes,amino acids,etc.It has beneficial functions,such as the anti-inflammatory,antitumor,hepatoprotective,and anti-aging effects.Among these,P.notoginseng polysaccharides(PNPs)have been exploited because of their extensive pharmacological effects,being ranked as one of the current research hotspots,especially for the functional foods and medical practice.In this review,the literature related to PNPs in the past 20 years was surveyed and analyzed using both the China National Knowledge Infrastructure(CNKI)and Web of Science(WOS)databases.The visualization diagram shows that current studies on PNPs mainly focus on the antioxidant and immunomodulatory activities and structural characterization.In addition,the extraction,separation,purification,chemical analysis,structural characteristics,bioactivities,and applications of PNPs are outlined,in detail,aimed to provide valuable information for the further study,development,and utilization regarding PNPs.
基金funding support from the National Natural Science Foundation of China(Grant No.42007269)the Young Talent Fund of Xi'an Association for Science and Technology(Grant No.959202313094)the Fundamental Research Funds for the Central Universities,CHD(Grant No.300102263401).
文摘The characterization and clustering of rock discontinuity sets are a crucial and challenging task in rock mechanics and geotechnical engineering.Over the past few decades,the clustering of discontinuity sets has undergone rapid and remarkable development.However,there is no relevant literature summarizing these achievements,and this paper attempts to elaborate on the current status and prospects in this field.Specifically,this review aims to discuss the development process of clustering methods for discontinuity sets and the state-of-the-art relevant algorithms.First,we introduce the importance of discontinuity clustering analysis and follow the comprehensive characterization approaches of discontinuity data.A bibliometric analysis is subsequently conducted to clarify the current status and development characteristics of the clustering of discontinuity sets.The methods for the clustering analysis of rock discontinuities are reviewed in terms of single-and multi-parameter clustering methods.Single-parameter methods can be classified into empirical judgment methods,dynamic clustering methods,relative static clustering methods,and static clustering methods,reflecting the continuous optimization and improvement of clustering algorithms.Moreover,this paper compares the current mainstream of single-parameter clustering methods with multi-parameter clustering methods.It is emphasized that the current single-parameter clustering methods have reached their performance limits,with little room for improvement,and that there is a need to extend the study of multi-parameter clustering methods.Finally,several suggestions are offered for future research on the clustering of discontinuity sets.
基金supported by grants from the National Natural Science Foundation of China(Nos.42002050 and 42072174).
文摘Opening-mode fractures play a crucial role in shale reservoirs,as they serve as flow channels and provide storage space for hydrocarbons.The shale reservoirs in the Permian Lucaogou Formation of the Junggar Basin,NW China,record multi-stage tectonic and diagenetic processes that created multi-stage natural fractures,thereby contributing to the oil content differentiation within the formation.Effective identification and characterization of natural fractures is vital for the efficient recovery of shale oil in the Jimsar Sag.We combine outcrop observations,drill core analyses,thin section examinations,and well log analyses to determine the characteristics of fractures in the shale reservoirs and their modes of development.We also establish multi-parameter evaluation index criteria and an evaluation system for fractures using statistical analyses.The shale reservoirs of the Lucaogou Formation in the Jimsar Sag host three main types of fracture:tectonic fractures,diagenetic fractures,and overpressure fractures.Conventional well logging,imaging logging,and core observations demonstrate that the fractured shale reservoir section has gamma-ray counts(GR)of>75 API,shallow laterolog resistivities of<80Ω·m,neutron densities of<2.40 g/cm3,neutron porosities of>27%,and interval transit times of>23.77μs/m,fracture density exceeding 3 fractures/m,and average porosity ranging from 0.2%to 0.3%in the lower sweet spots.The lower sweet spot(P2l12)of the Lucaogou Formation exhibits the highest degree of fracture development.Our detailed characterization reveals high fracture permeabilities and porosities in the upper and lower sweet spots(P2l22 and P2l12),with higher values in the latter.In addition,we present a novel rose diagram method to represent various fracture parameters.The best-developed tectonic fractures in the Lucaogou Formation strike ENE-WSW,have an average linear density of 1.65 fractures/m,an average aperture of 0.25 mm,an average length of 8.7 cm,and the highest proportion of unfilled fractures.Our study shows that a combination of field observations,drill core analyses,microscopic observations,and well logging provides a solid foundation for investigating the mechanisms of fracture formation in shale reservoirs.
文摘In the Republic of Benin,as in many other West African countries,urban areas have experienced rapid popula-tion growth in recent years.This situation has led to an increasing demand for sanitation facilities,necessitating regular emptying of these systems.In a bid to reduce health risks and protect the surrounding natural environment,the manage-ment of the by-products from these systems has become a significant concern for decision-makers at various levels.This study aims to characterize fecal sludge at the Abomey-Calavi treatment station and suggest a mixed biological treatment approach.Fifteen sewage sludge samples were collected in 1,500 ml plastic bottles from Adjagbo’s Sewage Treatment Station,operated by SGDS-SA,a Waste Management and Sanitation company.Physico-chemical parameters were de-termined using spectrophotometric analysis.Colonies were enumerated using membrane filtration and inoculation.Cor-relation analysis was performed on sewage sludge samples.The main results indicate an alkaline character(pH>7)and a high organic pollutant load in the fecal sludge,with average concentrations of Chemical Oxygen Demand(COD)and Biochemical Oxygen Demand over 5 days(BOD_(5))at 18,730 mg O_(2).L^(-1)and 6,612 mg O_(2).L^(-1),respectively.The COD/BOD_(5) ratio of 2.83 suggests that the material is partially biodegradable.Furthermore,the nutrients exhibited high con-centrations of nitrates,with an average value of 4,786 mg.L^(-1),while nitrites,ammoniacal nitrogen,and orthophosphates had average concentrations of 22.48 mg.L^(-1),119.74 mg.L^(-1),and 239.0 mg.L^(-1),respectively.This study characterized fe-cal sludge at the Abomey-Calavi treatment station and suggests a mixed biological treatment approach.
基金supported by Fundamental Research Funds for the Central Universities(No.2024YJS078)the National Natural Science Foundation of China(No.62341127,62221001 and 62171021)+1 种基金the Fundamental Research Funds for the Natural Science Foundation of Jiangsu Province,Major Project(No.BK2021200)the Key Research and Development Program of Zhejiang Province(No.2023C01003)。
文摘With the development of wireless communication,the fifth generation mobile communication technology(5G)has emerged as a hot topic in highspeed railway communication system and has moved towards industrial application.Investigating the radio propagation characteristics in 5G high-speed train(HST)scenarios is essential for enhancing wireless coverage and overall system performance.We propose a novel 5G passive sounding scheme to extract channel impulse responses(CIRs)using channel state information reference signals(CSI-RS)from the target 5G base station(BS).Detailed procedures for timefrequency synchronization,CSI-RS detection and extraction are presented through simulations.Through the laboratory work involving absolute power calibration,phase coherence calibration and power delay profile(PDP)validation,we validate the accuracy and performance of the developed platform.Furthermore,a measurement campaign was conducted in HST scenarios encompassing both residential and undeveloped areas.The path loss(PL)model and the channel characteristics including stationarity interval(SI),multipath components(MPCs),shadow fading(SF),Rician K-factor,root mean square(RMS)delay spread and received correlation coefficients are analyzed and fitted.The estimated channel characteristics and the statistical model presented in this paper will contribute to the research on HST radio propagation and the development of 5G railway communication systems.
