检索结果-南通市图书馆

Leaching of rare Earth elements from an Illinois basin coal source

在线全文

学校读者我要写书评

暂无评论

Journal of rare Earths 2019年第3期37卷 312-321页

作者： X.Yang J.Werner r.q.Honaker Department of Mining Engineering University of Kentucky

The existence of rare earth elements(rEEs) in coal sources at elevated concentrations has been the focus of several studies over the past decade. However, limited research has been conducted on methods to recover and refine the rEEs. This paper reports the results of a detailed study into the potential of selectively recovering rEEs in an Illinois basin coal source by leaching. Leaching characteristics are obtained for several segments obtained from a core sample as well as three different reject materials collected at a coal processing plant. Using a 1.2 mol/L sulfuric acid solution at 75 ℃,over 60% rEE recovery is achieved from the direct floor and an inner parting material as well as the coal-rich core segments that are pretreated by low-temperature plasma oxidation to obtain access to the microdispersed mineral matter. In the leachable parting material, fluorapatite is detected by XrD analysis,which is one of the more soluble phosphate minerals with a documented association with rEEs. For the three plant reject samples, the leaching recovery values obtained for the heavy rEEs are higher than those obtained for the light rEEs under the standard leaching conditions and when 0.1 mol/L(NH_4)_2SO_4 was used to extract rEEs by an ion exchange mechanism. Thermal activation by roasting or chemical activation by pretreatment using 8 mol/L NaOH solution increases the total rEE recovery with significantly higher gains obtained for the light rEEs. Leaching kinetics are relatively fast within the first 2 h and then slow to provide relatively low overall recovery values under the standard test conditions for the coarse and fine reject samples. However, significantly higher recovery values are realized when treating mixed-phase(middling) particles existing within the coarse reject material.

关键词： Leaching Coal Thermal activation Chemical activation rare earth elements

Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S r Wu B q Wang Z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the reissner-Nordström-de Sitter BH surrounded by quintessence(rN-dSq).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the rN-dSq under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the rN-dSq are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

Nodal superconducting gap in LiFeP revealed by NMr:Contrast with LiFeAs

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第4期30卷 113-118页

作者： A F Fang r Zhou H Tukada J Yang Z Deng X C Wang C q Jin Guo-qing zheng Department of Physics Beijing Normal UniversityBeijing 100875China Institute of Physics Chinese Academy of Sciencesand Beijing National Laboratory for Condensed Matter PhysicsBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Department of Physics Okayama UniversityOkayama 700-8530Japan

Identifying the uniqueness of FeP-based superconductors may shed new lights on the mechanism of superconductivity in ***,we report nuclear magnetic resonance(NMr) studies on LiFeP and LiFeAs which have the same crystal structure but different pnictogen *** NMr spectrum is sensitive to inhomogeneous magnetic fields in the vortex state and can provide the information on the superconducting pairing symmetry through the temperature dependence of London penetration depth λ_(L).We find that λ_(L) saturates below T~0.2 T_(C) in LiFeAs,where T_(C) is the superconducting transition temperature,indicating nodeless superconducting ***,by using a two-gaps model,we simulate the temperature dependence of λ_(L) and obtain the superconducting gaps of LiFeAs,as Δ_(1)=1.2 kB T_(C) and Δ_(2)=2.8 k_(B)T_(C),in agreement with previous result from spin-lattice *** LiFeP,in contrast,λ_(L) does not show any saturation down to T~0.03 T_(C),indicating nodes in the superconducting gap ***,we demonstrate that strong spin fluctuations with diffusive characteristics exist in LiFeP,as in some cuprate high temperature superconductors.

关键词： iron-based superconductor nuclear magnetic resonance superconducting pairing symmetry spin fluctuations

SUBCONVErGENCE OF FINITE ELEMENTS AND A SELF-ADAPTIVE ALGOrITHM

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1996年第4期14卷 336-344页

作者： Zhu q D Lin q 南京大学数力系江苏南京中科院系统科学所北京

ELECTrOCHEMICAL IMPEDANCE SPECTrOSCOPY DUrING COrrOSION PrOCESS OF 8090 Al-Li ALLOY IN EXCO SOLUTION

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 894-901页

作者： J.F.Li Z.q.zheng C.Y.Tan S.C.Li Z.Zhang J.q.Zhang CollegeofMaterialsScienceandEngineering CentralSouthUniversityChangsha410083China／／DepartmentofChemistryZhejiangUniversityHangzhou310027China CollegeofMaterialsScienceandEngineering CentralSouthUniversityChangsha410083China DepartmentofChemistry ZhejiangUniversityHangzhou310027China DepartmentofChemistry ZhejiangUniversityHangzhou310027China／／StateKeyLaboratoryforCorrosionand.ProtectionInstituteofMetalResearchTheChineseAcademy

The corrosion behavior and electrochemical impedance spectroscopy (EIS) features of 8090 Al-Li alloys in EXCO solution were investigated, and the EIS was simulated using an equivalent circuit. At the beginning of immersion in EXCO solution, the EIS is comprised by a depressed capacitive arc at high-mediate frequency and an inductive arc at low frequency, and the inductive component decreases and disappears with im- mersion time. Once exfoliation or severe pitting corrosion is produced, two capacitive arcs appear in the EIS. These two capacitive arcs are originated from the two parts of the corroded alloy surface, the original flat alloy surface and the new inter-face exposed to the aggressive EXCO solution due to the exfoliation or pitting corrosion. Some corrosion development features of 8090 Al-Li alloys in EXCO solution can be obtained through simulated EIS information.

关键词： Al-Li alloy, exfoliation, electrochemical impedance spectros- copy (EIS), EXCO solution

Stochastic Accelerated Alternating Direction Method of Multipliers for Hedging Communication Noise in Combined Heat and Power Dispatch

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2023年第2期9卷 696-706页

作者： Zhigang Li Xinyu Liang Fan Hu Wen Xiong renbo Wu J.H.zheng q.H.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China Guangzhou Power Supply Bureau Guangdong Power Grid Co.LtdGuangzhouChina

Combined heat and power dispatch(CHPD)opens a new window for increasing operational flexibility and reducing wind power *** power and district heating systems are independently controlled by different system operators;therefore,a decentralized solution paradigm is necessary for CHPD,in which only minor boundary information is required to be exchanged via a communication ***,a nonideal communication environment with noise could lead to divergence or incorrect solutions of decentralized *** bridge this gap,this paper proposes a stochastic accelerated alternating direction method of multipliers(SA-ADMM)for hedging communication noise in *** algorithm provides a general framework to address more types of constraint sets and separable objective functions than the existing stochastic *** from the single noise sources considered in the existing stochastic approximation methods,communication noise from multiple sources is addressed in both the local calculation and the variable update *** studies of two test systems validate the effectiveness and robustness of the proposed SAADMM.

关键词： Alternating direction method of multipliers combined heat and power dispatch communication noise decentralized optimization

PLASMA SPrAYED Ti AND HA COATINGS: A COMPArATIVE STUDY BETWEEN APS AND VPS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 339-344页

作者： X.B.zheng H.Ji J.q.Huang C.X.Ding ShanghaiInstituteofCeramics TheChineseAcademyofSciencesShanghai200050China

Titanium (Ti) and hydroxyapatite (HA) coatings have been prepared via air (APS) and vacuum plasma spraying (VPS), and then their composition, structure, bonding strength and bioactivity were examined. The results obtained reveal that in APS process many of Ti were oxidized, but in VPS the oxidization was avoided. VPS T i coating possesses better bonding condition than APS Ti coating. As for HA coat ing, higher crystallinity has been obtained while the coating was deposited by V PS as compared with APS. The simulated body fluid (SBF) tests show that both of APS and VPS HA coatings possess good bioactivity. As compared with APS, VPS is r ecommended as a better method to deposit Ti and HA coatings that can be applied as hard tissue replacement implants.

关键词： vacuum plasma spray Ti HA biocoating

Diagnostic value of amino acid consumption test on exocrine pancreatic insufficiency

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2000年第2期6卷 290-292页

作者： Lei ZM Li DY Li J Wang q He K zheng SL Gan YG Luzhou Med Coll Affiliated Hosp Dept Hepatobiliary Surg Luzhou 646000 Sichuan Peoples R China

INTrODUCTIONAmino acid consumption test (AACT) has a highsensitivity and specificity in evaluating exocrinepancreatic insufficiency,but its diagnostic valueto exocrine pancreatic insufficiency in Chinese hasnot been well *** this study,the oralreagent stimulating pancreatic secretion (O-AACT)was used instead of cerulein(I-AACT) for amidoacid consumption test and the dignostic efficiency ofO-AACT was evaluated and compared with I-AACTon the exocrine pancreatic insufficiency in Chinese.

关键词： pancreatic insufficiency/diagnosis aminoacid consumption test cerulein cholelithiasis

Variation Patterns of NLr Clusters in Arabidopsis thaliana Genomes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Communications 2020年第4期1卷 129-143页

作者： rachelle r.q.Lee Eunyoung Chae Department of Biological Sciences National University of SingaporeSingapore 117558Singapore

The nucleotide-binding domain and leucine-rich repeat(NLr)gene family is highly expanded in the plant lineage with extensive sequence and structure *** survey the landscape of NLr expansion,we mined the published long-read data generated by the resistance gene enrichment sequencing of 64 diverse Arabidopsis thaliana *** found that the hot spots of massive multi-gene NLr cluster expansion did not typically span the whole cluster;instead,they were restricted to a handful of,or only one,dominant radiation(s).All sequences in such a radiation were distinct from other genes in the cluster but not from each other in the clade,making it difficult to assign trustworthy reference-based orthologies when multiple reference genes were present in the ***,NLr genes can be broadly divided into two types:radiating or high-fidelity,where high-fidelity genes are well conserved and well separated from other clades.A similar distinction could be made for NLr clusters,depending on whether cluster size was determined primarily by extensive radiation or the presence of numerous high-fidelity *** also identified groups of well-conserved NLr clades that were missing from the Columbia-0 reference *** suggests that the classification of NLrs using gene IDs from a single reference accession can rarely capture all major paralogs in a cluster accurately and representatively and that a referenceagnostic perspective is required to properly characterize these additional ***,we present a quantitative visualization method for differentiating these situations in a given clade of interest.

关键词： NLr cluster evolution phylogenetics disease resistance plant immunity