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Extraction of rare earth elements from a South American ionic clay

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稀土学报:英文版 2023年第9期41卷 1408-1418,I0005页

作者： john Anawati Gisele Azimi laboratory for Strategic Materials Department of Chemical Engineering and Applied ChemistryUniversity of Toronto200 College StreetTorontoOntarioM5S3E5Canada Department of Materials Science and Engineering University of Toronto184 College StreetTorontoOntarioM5S 3E4Canada

Ionic clays,formed by the natural weathering of REE-bearing minerals and the adsorption of the resulting liberated REE ions onto the clay surface,are an important resource for critical rare earth elements(REEs).Here,a two-step desorption process using ammonium sulfate with active pH adjustment using sulfuric acid was developed to extract REEs from a South American *** desorption process was optimized using response surface methodology approach and the optimum operating conditions were determined to be 0.15 mol/l ammonium sulfate,pH 3,liquid to solid ratio of 3/1,and 25℃ with20 min residence *** is shown that this ionic clay is significantly different from previously reported clays,e.g.,from southern China,as it consists of three modes of REEs,including ion-exchanged REEs physically adsorbed on the clay surface,hydrolyzed REEs chemically adsorbed on the clay surface,and mineralized(non-desorbable) REEs within the *** investigations through progressive acidification during desorption and adsorption isotherms show that REE desorption/adsorption occurs due to the combined action of physical ion exchange adsorption and surface complexation chemical adsorption,with their relative importance depending on the pH of the system and the amount of sulfate anions present within the *** work supports overall efforts to utilize ionic clays as a relatively new resource for REEs to empower the development and adoption of modern green technologies such as wind turbines and electric vehicles.

关键词： Ionic clay Ion-exchange desorption Surface complexation Ammonium sulfate leaching Rare earths

Pathogenesis of fatty liver diseases and hepatocellular carcinoma

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liver Research 2022年第4期6卷 201-202页

作者： john Y.l.Chiang Tiangang li Integrative Medical Sciences Northeast Ohio Medical UniversityRootstownOHUSA Harold Hamm Diabetes Center Department of PhysiologyUniversity of Oklahoma Health Sciences CenterOklahoma CityOKUSA

The prevalence of fatty liver diseases has increased rapidly in recent years to about 25%*** liver diseases are multi-faceted in pathogenesis,disease phenotype,and *** is important to understand disease pathogenesis and mechanism in order to develop effective and safe drug therapy for treating fatty liver *** fatty liver disease(AFlD,or alcohol associ-ated liver disease)and viral hepatitis have been the major causes of liver transplant,liver cancer,and death.

关键词： diseases mechanism. liver

Changes in Typhoon Regional Heavy Precipitation Events over China from 1960 to 2018

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Advances in Atmospheric Sciences 2022年第2期39卷 272-283页

作者： Yangmei TIAN john lMCBRIDE Fumin REN Guoping lI Tian FENG College of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China State Key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Honorary School of Earth ScienceUniversity of Melbourneand Research and Development DivisionBureau of MeteorologyMelbourneVIC 3010Australia Haikou Meteorological Observatory Haikou Meteorological BureauHaikou 570100China

In earlier studies,objective techniques have been used to determine the contribution of tropical cyclones to precipitation(TCP)in a region,where the Tropical cyclone Precipitation Event(TPE)and the Regional Heavy Precipitation Events(RHPEs)are defined and *** this study,TPE and RHPEs are combined to determine the Typhoon Regional Heavy Precipitation Events(TRHPEs),which is employed to evaluate the contribution of tropical cyclones to regional extreme precipitation *** on the Objective Identification Technique for Regional Extreme Events(OITREE)and the Objective Synoptic Analysis Technique(OSAT)to define TPE,temporal and spatial overlap indices are developed to identify the combined events as *** daily precipitation data and TC best-track data over the western North Pacific from 1960 to 2018,86 TRHPEs have been *** contribute as much as 20%of the RHPEs,but100%of events with extreme individual precipitation *** major TRHPEs continued for approximately a week after tropical cyclone landfall,indicating a role of post landfall *** frequency and extreme intensity of TRHPEs display increasing trends,consistent with an observed positive trend in the mean intensity of TPEs as measured by the number of daily station precipitation observations exceeding 100 mm and 250 *** frequent landfalling Southeast and South China TCs induced more serious impacts in coastal areas in the Southeast and the South during 1990-2018 *** roles of cyclone translation speed and"shifts"in cyclone tracks are examined as possible explanations for the temporal trends.

关键词： typhoon regional heavy precipitation events changes temporal and spatial characteristics

Roles of raindrop impact in detachment and transport processes of interrill soil erosion

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International Soil and Water Conservation Research 2023年第4期11卷 592-601页

作者： Xunchang john Zhang USDA-ARS Grazinglands Research lab. El RenoOK73036USA

To date the roles of raindrop impact in sediment entrainment and transport processes of interrill soil erosion are not yet fully *** objectives are to 1)evaluate the effects of raindrop impact on sediment entrainment,2)systematically quantify the relative importance of raindrop-driven and flow-driven transport,and 3)characterize sediment size distributions in different sediment transport re-gimes.A loam soil with 48.4%sand and 23%clay was packed into flumes(l × W × H:1.8 × 0.5 × 0.1 m)and subjected to intensities of 60,90,120 mm h^(-1) at gradients of 5,10,and 16°.Air filter and tarp covers were used to vary impact energy and flow *** show that sediment is largely entrained by raindrop impact and transported by raindrop-impacted *** erosion consists of two composite processes:raindrop-induced detachment/entrainment and raindrop-impacted flow *** former includes direct detachment by raindrop impact and'flow detachment'.The latter includes raindrop-driven and flow-driven *** proportions between the two transports vary with slope steepness,slope length,flow depth(or flow discharge),rainfall intensity,and sediment ***-driven transport is competent but inefficient,while the opposite is true for flow-driven *** raindrop impact plays dual roles in detaching soil(and/or entraining sediment)and enhancing sediment transport,a drop energy factor must be included in interrill erosion models to adequately simulate the dual *** studies are required to derive a drop energy function that takes into consideration the rainfall energy dissipation by canopies of various plants under natural conditions.

关键词： Interrill erosionprocess Raindrop detachment Raindropentrainment Raindrop-driven transport Flow-driven transport Raindrop-flow interaction

Key challenges and approaches to addressing barriers in forest carbon offset projects

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Journal of Forestry Research 2022年第4期33卷 1109-1122页

作者： Chunyu Pan Anil Shrestha john lInnes Guomo Zhou Nuyun li Jinliang li Yeyun He Chunguang Sheng john-ONiles Guangyu Wang Faculty of Forestry University of British Columbia2424 Main MallVancouverBC V6T 1Z4Canada Zhejiang Prov Key lab of Carbon Cycling Forest Ecosystem Zhejiang A&F UniversityLinan 311300People’s Republic of China China Green Carbon Foundation No.18Hepingli DongjieBeijing 100714People’s Republic of China College of Economics and Management Northeast Forestry UniversityHarbin 150040People’s Republic of China University of California San Diego9500 Gilman DriveLa JollaSan DiegoCA 92093USA

Forest carbon offset(FCO)projects play an increasingly important role in mitigating climate change through market mechanisms in both compliance and voluntary ***,there are challenges and barriers to developing an FCO project,such as carbon leakage and cost-eff *** have been few attempts to summarize and synthesize all types and aspects of existing challenges and possible solutions for FCO *** paper systematically reviews and discusses the current challenges involved in developing FCO projects,and then draws on the experience and lessons of existing projects to show how those challenges were addressed in world-leading voluntary carbon standards,namely the Verifi ed Carbon Standard,the American Carbon Registry,the Climate Action Reserve,and Plan *** voluntary markets have rich experience in FCO projects and are responsible for a signifi cant share of the *** the 53 publications used in this analysis,three broad thematic categories of challenges *** were related to methodology,socio-economic implications,and *** challenges,particularly additionality,permanence,and leakage,were the focus of 46%of the selected research papers,while socio-economic challenges,including transaction,social,and opportunity costs,were addressed by 35%.The remaining 19%of the research articles focused on implementational challenges related to monitoring,reporting,and verifi *** voluntary standards adequately addressed most of the methodological and implementational barriers by adopting various ***,the standards did not adequately address socio-economic issues,despite these being the second most frequently discussed theme in the papers *** research is clearly needed on the socio-economic challenges involved in the development of FCO *** the development of high-quality forestry carbon off set projects,there are many challenges and no simple,universal recipe for addressi

关键词： Forest carbon Offset schemes Market mechanisms Challenges Opportunities

Optimization of specific cell-peptide interactions at the bio-material interface via regulation of nonspecific biofouling interactions

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Science China Chemistry 2020年第2期63卷 143-144页

作者： john l.Brash Department of Chemical Engineering School of Biomedical EngineeringMcMaster University

Materials that interact with biological systems in a wellcontrolled,predictable manner are highly sought after for numerous biomedical and biotechnological *** example,it is essential that devices such as stents or heart valves in the blood stream of patients do not cause thrombosis or infection,or that biosensors do not lose their function due to adverse interactions with the bio environment.A general approach to the design of biointerfaces that addresses this need has been pursued over a number of years[1].It has two elements:(1)prevention of non-specific interfacial interactions,and(2)promotion of specific biointeractions required for the intended functioning of the *** practice this means preventing all interactions except for the desired one(s).With respect to the first point it should be appreciated that biological species such as proteins and cells have a natural affinity for the interfacial ***,the realization of a surface that eliminates the adsorption/adhesion of these species is extremely *** of PEO/PEG,other hydrophilic polymers(PVP,PHEMA),and zwitterionic polymers[2]to the surface is the most common strategy to achieve“bio-resistance”.Regarding the second point,the surface must be designed so that it interacts selectively and exclusively with the component(s)(proteins,cells)that will give the desired *** this purpose,“ligands”that bind these specific components are incorporated into the surface[3].

关键词： desired interfacial realization

Ionic conductivity anomaly in soil cover——Exploration of blind mineralization beneath regolith cover

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Science China Earth Sciences 2010年第5期53卷 649-656页

作者： KEElING john l. Primary Industries and Resources South Australia (PIRSA)

This paper briefly describes the formation of ionic conductivity anomalies in soil cover, and the characteristics of ionic composition that forms conductivity anomalies, based on the theory of geoelectrochemical halo. Based on some practical results of soluble ions in soil cover and soil conductivity derived from a number of mining areas of both China and overseas, here we present the correlation of a conductivity anomaly with the ionic composition and establish a model for the formation of conductivity anomalies in soil cover. The results indicate that the formation of a conductivity anomaly is not a simple transformation of a secondary geochemical anomaly. A conductivity anomaly is formed as the result of electrochemical and chemical processes, by transformation of orebody into various ionic haloes through four physicochemical processes: 1) dissolution of the orebody, 2) migration of dissolved matter, 3) conversion of matter near the surface, and 4) the formation of ionic conductivity anomalies. The conductivity anomaly, as a physical parameter, essentially represents the integration of various geochemical compositions and is controlled by a set of particular ionic groups.

关键词： ionic conductivity regolith mineralisation exploration

A General Algorithm for Calculating Irreducible Brillouin Zones

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Communications in Computational Physics 2022年第2期31卷 495-515页

作者： Jeremy J.Jorgensen john E.Christensen Tyler J.Jarvis Gus l.W.Hart Department of Physics and Astronomy Brigham Young UniversityProvoUtah84602USA Department ofMathematics BrighamYoungUniversityProvoUtah84602USA

Calculations of properties of materials require performing numerical integrals over the Brillouin zone(BZ).Integration points in density functional theory codes are uniformly spread over the BZ(despite integration error being concentrated in small regions of the BZ)and preserve symmetry to improve computational *** points over an irreducible Brillouin zone(IBZ),a rotationally distinct region of the BZ,do not have to preserve crystal symmetry for greater *** freedom allows the use of adaptive meshes with higher concentrations of points at locations of large error,resulting in improved algorithmic *** have created an algorithm for constructing an IBZ of any crystal structure in 2D and *** algorithmuses convex hull and half-space representations for the BZ and IBZ to make many aspects of construction and symmetry reduction of the BZ *** algorithm is simple,general,and available as open-source software.

关键词： Brillouin zone irreducible Brillouin zone

Synthesis of liSm_(0.01)Mn_(1.99)O_4 by molten salt technique

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Journal of Rare Earths 2010年第2期28卷 255-259页

作者： M Helan l john Berchmans Department of Chemistry Jamal Mohamed College (Autonomous) Electropyrometallurgy Division Central Electrochemical Research Institute

Samarium substituted lithium manganese oxide powders were successfully prepared by molten-salt synthesis(MSS) using eutectic mixture of liCl,SmCl3.6H2O and MnO2 salt at 700 °*** synthesis was carried out in open *** crystalline powders were characterized for their phase identification using X-ray diffraction(XRD) *** physico-chemical properties of the samarium substituted lithium manganese oxide powders were investigated by thermal analysis(TGA/DTA),FT-IR spectroscopy,EDAX,electron par...

关键词： liSm0.01Mn1.99O4 molten salt synthesis cathode materials rare earth ion