The copper polymetallic deposits and resource potential in the Tibet Plateau

Many large and super-large copper deposits have been discovered and explored in the Tibet Plateau,which makes it the most important copper resource reserve and development base in China.Based on the work of the research team,the paper summarizes the geological characteristics of the main copper deposits in Tibet and puts forward a further prospecting direction.A series of large accumulated metal deposits or ore districts from subduction of Tethys oceanic crust to India-Asia collisionhave been discovered,such as Duolong Cu(Au)ore district and Jiama copper polymetallic deposit.The ore deposits in the Duolong ore district are located in the lowstand domain,the top of lowstand domain,and the highstand domain of the same magmatic-hydrothermal metallogenic system,and their relative positions are the indicators for related deposits in the Bangong Co-Nujiang metallogenic belt.The polycentric metallogenic model of the Jiama copper polymetallic deposit is an important inspiration for the exploration of the porphyry mineralization related to collision orogeny.Further mineral exploration in the Tibet Plateau should be focused on the continental volcanic rocks related to porphyry-epithermal deposits,orogenic gold deposits,hydrothermal Pb-Zn deposits related to nappe structures,skarn Cu(Au)and polymetallic deposits,and the Miocene W-Sn polymetallic deposits.

Geology and mineralization of the Tiegelongnan supergiant porphyry-epithermal Cu(Au, Ag) deposit(10 Mt) in western Tibet, China: A review

The Tiegelongnan Cu(Au,Ag)deposit in central Tibet contains more than 10 Mt of copper ranking 29 th in the world.It is characterized by typical porphyry-epithermal alteration and mineralization.In order to improve the understanding of porphyry-epithermal copper deposit in Tibet,new zircon U-Pb age and sulfur isotope data along with published data in the Tiegelongnan are presented to investigate the formation and preservation mechanism.Ore-related intrusive rocks in the Tiegelongnan including Early Cretaceous(about 120 Ma)granodiorite porphyry and diorite porphyry are closely related to the northward subduction of Bangongco-Nujiang ocean.Sulfur mainly comes from deep magma,and ore-forming fluid is affected by both magmatic and meteoric water.The metallogenic setting of Tiegelongnan is consistent with those of Andean porphyry copper deposits in South America.The cover of the Meiriqiecuo Formation volcanic rocks,Lhasa-Qiangtang collision and India-Eurasian collision have significance in the preservation and uplift of the deposit.The formation,preservation and discovery of Tiegelongnan play an important role in exploration of ancient porphyry-epithermal deposits in Tibet.

Characteristic mode analysis of wideband high-gain and low-profile metasurface antenna

A wideband high-gain and low-profile metasurface antenna is proposed by analyzing characteristic quantities and parameters in the characteristic modes(CMs). The detailed modal current and modal weighting coefficient are analyzed to explain the broadband operation and high gain. A dominant characteristic mode is well excited, leading to a broadband operation. The mode behaviors of the excitation are changed to suppress the unwanted higher-order modes and improve the radiation performance by changing the widths of two patches. The measured impedance bandwidth for-10 dB is 39.8%(5.3 GHz–7.94 GHz) with a gain of 7.8 dBi–10.04 dBi over the operating bandwidth.

Analysis of long noncoding RNA-associated competing endogenous RNA network in glucagon-like peptide-1 receptor agonist-mediated protection inβcells

BACKGROUND Long noncoding RNAs(lncRNAs)and mRNAs are widely involved in various physiological and pathological processes.The use of glucagon-like peptide-1 receptor agonists(GLP-1RAs)is a novel therapeutic strategy that could promote insulin secretion and decrease the rate ofβ-cell apoptosis in type 2 diabetes mellitus(T2DM)patients.However,the specific lncRNAs and mRNAs and their functions in these processes have not been fully identified and elucidated.AIM To identify the lncRNAs and mRNAs that are involved in the protective effect of GLP-1RA inβcells,and their roles.METHODS Rat gene microarray was used to screen differentially expressed(DE)lncRNAs and mRNAs inβcells treated with geniposide,a GLP-1RA.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analyses were performed to assess the underlying functions of DE mRNAs.Hub mRNAs were filtered using the STRING database and the Cytoscape plugin,CytoHubba.In order to reveal the regulatory relationship between lncRNAs and hub mRNAs,their co-expression network was constructed based on the Pearson coefficient of DE lncRNAs and mRNAs,and competing endogenous RNA(ceRNA)mechanism was explored through miRanda and TargetScan databases.RESULTS We identified 308 DE lncRNAs and 128 DE mRNAs with a fold change filter of≥1.5 and P value<0.05.GO and KEGG pathway enrichment analyses indicated that the most enriched terms were G-protein coupled receptor signaling pathway,inflammatory response,calcium signaling pathway,positive regulation of cell proliferation,and ERK1 and ERK2 cascade.Pomc,Htr2a,and Agtr1a were screened as hub mRNAs using the STRING database and the Cytoscape plugin,CytoHubba.This result was further verified using SwissTargetPrediction tool.Through the co-expression network and competing endogenous(ceRNA)mechanism,we identified seven lncRNAs(NONRATT027738,NONRATT027888,NONRATT030038,etc.)co-expressed with the three hub mRNAs(Pomc,Htr2a,and Agtr1a)based on the Pearson coefficient of the expression levels.These lncRNAs regulated hub mRNA functions by competing with six miRNAs(rno-miR-5132-3p,rno-miR-344g,rno-miR-3075,etc.)via the ceRNA mechanism.Further analysis indicated that lncRNA NONRATT027738 interacts with all the three hub mRNAs,suggesting that it is at a core position within the ceRNA network.CONCLUSION We have identified key lncRNAs and mRNAs,and highlighted here how they interact through the ceRNA mechanism to mediate the protective effect of GLP-1RA inβcells.

Linear Viscoelasticity of ABA-type Vitrimer Based on Dioxaborolane Metathesis

In this study,we synthesized a series of ABA-type vitrimers by crosslinking the short A moieties of precursors with a bifunctional crosslinker and evaporating the small molecular byproduct.The vitrimer samples thus prepared exhibit linear viscoelasticity dependent on the length of A moiety as well as the content of the crosslinks.When the average number of A monomers per end moiety m=1.1,the crosslinker can only extend the chain but not crosslink the chain.When m becomes 2.8 or higher,introducing a crosslinker first leads to the gelation,whereas excess in crosslinker molecules leads opening of the crosslinking sites and accordingly reentry into the sol regime.Surprisingly,a further increase in the length of the A moieties increases the relaxation time much weaker than the exponential increase seen for the physically crosslinked ABAtype ionomers.We attribute this difference to the distinct relaxation mechanisms:the relaxation of the vitrimer samples is based on relatively independent exchange reactions,which contrasts with the ABA-type ionomers that relax through the collective hopping of connected ionic groups from one ion aggregate to another.

Particulate matter capturing over manganese dioxides with different crystal structures

Particulate matter(PM)is the main contributor to air pollution,and filtration has been reported to be promising for PM capturing.Considering the complexity of polluted air(volatile organic compounds(VOCs)and ozone are likely concomitant with PM particles)and in view of the versatility of MnO_(2) for the degradation of VOCs and ozone,the feasibility of MnO_(2) materials as PM filteringmediawas investigated in this study,and the effect of crystal structure on PM filtration was clarified.Compared with the layeredδ-MnO_(2),the MnO_(2) with tunnel structure(including 1×2-,2×2-and 3×3-MnO_(2))exhibited greatly enhanced PM removal efficiencies,and particularly,the 3×3-MnO_(2) possessed not only significant activity for adsorbing PM particles but also high utilization efficiency of the active surface.Physicochemical properties of the adsorbents were studied by XRD,ATR,isothermal N_(2) adsorption,SEM and(HR)TEM.The correlation between pore characteristics and particle elimination activity demonstrates that the most developed mesoporous structure of the 3×3-MnO_(2) sample played an important role in strengthening the PM adsorption capability.Further comparison of the surface properties of the fresh and spent samples reveals that with respective to the occasion ofδ-MnO_(2),the structure of 3×3-MnO_(2) was robust enough to resist collapse after PM capturing and the great accommodation of the inorganic and organic PM substances in the voluminous pores induced strong affinity between PM particles and 3×3-MnO_(2).Thereby,a higher particle filtration ability was retained.

An efficient lossy link localization approach for wireless sensor networks

Network fault management is crucial for a wireless sensor network(WSN) to maintain a normal running state because faults(e.g., link failures) often occur. The existing lossy link localization(LLL) approach usually infers the most probable failed link set first, and then gives the fault hypothesis set. However, the inferred failed link set contains many possible failures that do not actually occur. That quantity of redundant information in the inferred set can pose a high computational burden on fault hypothesis inference, and consequently decreases the evaluation accuracy and increases the failure localization time. To address the issue, we propose the conditional information entropy based redundancy elimination(CIERE), a redundant lossy link elimination approach, which can eliminate most redundant information while reserving the important information. Specifically, we develop a probabilistically correlated failure model that can accurately reflect the correlation between link failures and model the nondeterministic fault propagation. Through several rounds of mathematical derivations, the LLL problem is transformed to a set-covering problem. A heuristic algorithm is proposed to deduce the failure hypothesis set. We compare the performance of the proposed approach with those of existing LLL methods in simulation and on a real WSN, and validate the efficiency and effectiveness of the proposed approach.