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Geochemistry and depositional environment of fuchsite quartzites from Sargur Group,western Dharwar Craton,India

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Acta Geochimica 2024年第3期43卷 555-570页

作者： C.S.Sindhuja G.Harshitha C.Manikyamba K.S.V.Subramanyam CSIR(council of Scientific and industrial research)-national Geophysical research institute(NGRI) Uppal RoadHyderabad 500007India

Meso-Neoarchean fuchsite quartzites are present in different stratigraphic positions of Dharwar Craton including the oldest(~3.3 Ga)Sargur Group of western Dharwar *** present study deals with the petro-graphic and geochemical characteristics of the fuchsite quartzites from the Ghattihosahalli belt to evaluate their genesis,depositional setting and the enigma involved in the ancient sedimentation *** major mineral assemblages include quartz,fuchsite,and feldspars along with accessory kyanite and *** geochemical com-positions are characterized by high SiO_(2),Al_(2)O_(3),low MgO,CaO,strongly enriched Cr(1326–6899 ppm),Ba(1165–3653 ppm),Sr(46–210 ppm),V(107–868 ppm)and Zn(11–158 ppm)contents compared to the upper continental crust(UCC).The UCC normalized rare earth element(REE)patterns are characterized by depleted light REE[(La/Sm)UCC=0.33–0.95]compared to heavy REE[(Gd/Yb)_(UCC)=0.42–1.65]with conspicuous positive Eu-anomalies(Eu/Eu^(*)=1.35–18.27)characteristic of hydrothermal solutions evidenced through the interlayered *** overall major and trace element systematics reflect a combined mafic-felsic provenance and suggest their deposition at a passive continental margin *** comprehensivefield,petrographic,and geo-chemical studies indicate that these quartzites are infiltrated by Cr-richfluids released during high-grade metamorphism of associated ultramafic *** Sargur and the subse-quent Dharwar orogeny amalgamated diverse lithounits from different tectonic settings,possibly leading to the release of Cr-richfluids and the formation of fuchsite quartzite during or after the *** sug-gest a pre-existing stable crust prior to the Sargur Group and the link between orogenic events and various mineral deposits in the Dharwar Craton.

关键词： Dharwar Craton Ghattihosahalli Fuchsite quartzite Provenance Depositional setting

Electroluminescence from pure resonant states in hBN-based vertical tunneling junctions

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Light(Science & Applications) 2024年第8期13卷 1557-1564页

作者： Magdalena Grzeszczyk Kristina Vaklinova Kenji Watanabe Takashi Taniguchi Konstantin SNovoselov Maciej Koperski institute for Functional Intelligent materials National University of SingaporeSingapore 117544Singapore research Center for Functional materials National Institute for Materials ScienceTsukuba 305-0044Japan International Center for materials Nanoarchitectonics National Institute for Materials ScienceTsukuba 305-0044Japan Department of materials Science and Engineering National University of SingaporeSingapore 117575Singapore

Defect centers in wide-band-gap crystals have garnered interest for their potential in applications among optoelectronic and sensor ***,defects embedded in highly insulating crystals,like diamond,silicon carbide,or aluminum oxide,have been notoriously difficult to excite electrically due to their large internal *** address this challenge,we realized a new paradigm of exciting defects in vertical tunneling junctions based on carbon centers in hexagonal boron nitride(hBN).The rational design of the devices via van der Waals technology enabled us to raise and control optical processes related to defect-to-band and intradefect *** fundamental understanding of the tunneling events was based on the transfer of the electronic wave function amplitude between resonant defect states in hBN to the metallic state in graphene,which leads to dramatic changes in the characteristics of electrons due to different band structures of constituent *** our devices,the decay of electrons via tunneling pathways competed with radiative recombination,resulting in an unprecedented degree of tuneability of carrier dynamics due to the significant sensitivity of the characteristic tunneling times on the thickness and structure of the *** enabled us to achieve a high-efficiency electrical excitation of intradefect transitions,exceeding by several orders of magnitude the efficiency of optical excitation in the sub-band-gap *** work represents a significant advancement towards a universal and scalable platform for electrically driven devices utilizing defect centers in wide-band-gap crystals with properties modulated via activation of different tunneling mechanisms at a level of device engineering.

关键词： carbide tunneling defect

Exploring the ultrahigh rolling contact fatigue life of M50 bearing steel by adjusting the cryogenic sequence

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Journal of materials Science & Technology 2024年第2期169卷 243-250页

作者： Xin Cai Xiaoqiang Hu Xingyu Lu Hongwei Liu Yanfei Cao Dianzhong Li Shenyang national Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The influence of different cryogenic sequences on the rolling contact fatigue(RCF)life of M50-bearing steel has been *** results show that direct cryogenic treatment after quenching can effectively improve RCF *** L_(10)life is strikingly 5 times longer than that with cryogenic treatment after *** is caused by the distinct lattice construction of martensite and the transformation of retained *** secondary nanocarbides and fine twins are formed via cryogenic treatment before tem-pering compared with cryogenic treatment after *** improvement in the RCF life of the steel is attributed to the joint effects of the secondary nanocarbides and twin boundaries with a width of 5-13 nm,which delays significantly crack initiation and *** study highlights a common method to improve the service life of high-carbon and high-alloy steels by adjusting the cryogenic se-quence.

关键词： M50 steel Cryogenic treatment Rolling contact fatigue life Carbide Twin

Two-Dimensional Metallophthalocyanine Nanomaterials for Electrocatalytic Energy Conversion

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Energy & Environmental materials 2024年第4期7卷 364-385页

作者： Xinqi Wang Shaohui Sun Jiahao Yao Hao Wan Renzhi Ma Wei Ma School of Chemical Engineering and Zhongyuan Critical Metals Laboratory Zhengzhou University research Center for materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS)

Crowing energy demand drives the rapid development of clean and reliable energy *** the past years,the exploration of novel materials with considerable efficiency and durability has drawn attention in the area of elec... 详细信息

关键词： conjugated nanostructure electrocatalysis 2D metallophthalocyanines

Unraveling light localization in quasi-periodic photonic lattices

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Science China Chemistry 2024年第9期67卷 2787-2788页

作者： Gianluigi Zito institute of Applied Sciences and Intelligent Systems National Research Council of ItalyVia Pietro Castellino111Napoli 80131Italy

Light localization has transformative implications for advancing the fields of chemistry and physics,enabling new approaches in sensing,imaging,energy harvesting,photochemical catalysis,molecular-scale optoelectronic devices,and information processing and data *** term refers to the confinement of electromagnetic waves(light)within a small spatial region,typically much smaller than the wavelength of the light itself[1].

关键词： light periodic quasi

Two-stage dynamic recrystallization and texture evolution in Al-7Mg alloy during hot torsion

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International Journal of Minerals,Metallurgy and materials 2024年第8期31卷 1900-1911页

作者： Kwang Tae Son Chang Hee Cho Myoung Gyun Kim Ji Woon Lee School of Mechanical Industrialand Manufacturing EngineeringOregon State UniversityCorvallis OR 97331USA Department of materials Science Engineering Northwestern UniversityEvanston IL 60208USA research institute of industrial Science and Technology(RIST) Pohang 37673Rep.of Korea Division of Advanced materials Engineering Kongju National UniversityCheonan 31080Rep.of Korea Center for Advanced materials and Parts of Powders Kongju National UniversityCheonan 31080Rep.of Korea

Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500℃ and strain rates between 0.05 and 5 s^(-1) to explore the progressive dynamic recrystallization(DRX)and texture *** DRX behavior of the alloy manifested two distinct stages:Stage 1 at strain of≤2 and Stage 2 at strains of≥*** Stage 1,there was a slight increase in the DRXed grain fraction(X_(DRX))with predominance of discontinuous DRX(DDRX),followed by a modest change in X_(DRX) until the transition to Stage *** 2 was marked by an accelerated rate of DRX,culminating in a substantial final X_(DRX) of~*** backscattered diffraction(EBSD)analysis on a sample in Stage 2 revealed that continuous DRX(CDRX)predominantly occurred within the(121)[001]grains,whereas the(111)[110]grains underwent a geometric DRX(GDRX)evolution without a noticeable sub-grain ***,a modified Avrami’s DRX kinetics model was utilized to predict the microstructural refinement in the Al-7Mg alloy during the DRX *** this kinetics model did not accurately capture the DDRX behavior in Stage 1,it effectively simulated the DRX rate in Stage *** texture index was employed to assess the evolution of the texture isotropy during hot-torsion test,demonstrating significant improvement(>75%)in texture randomness before the commencement of Stage *** initial texture evolution is attributed to the rotation of parent grains and the substructure evolution,rather than to an increase in X_(DRX).

关键词： Al-7Mg alloys hot deformation hot torsion tests dynamic recrystazlliation microstructure texture

Advancements in nanotechnology for the delivery of phytochemicals

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Journal of Integrative Medicine 2024年第4期22卷 385-398页

作者： Divya Chauhan Pavan K.Yadav Nazneen Sultana Arun Agarwal Saurabh Verma Manish K.Chourasia Jiaur R.Gayen Division of Pharmaceutics and Pharmacokinetics Central Drug Research InstituteCouncil of Scientific and Industrial ResearchLucknow 226031Uttar PradeshIndia Academy of Scientific and Innovative research Ghaziabad 201002Uttar PradeshIndia

Phytosomes(phytophospholipid complex) are dosage forms that have recently been introduced to increase the stability and therapeutic effect of herbal medicine. Currently, bioactive herbs and the phytochemicals they contain are considered to be the best remedies for chronic diseases. One promising approach to increase the efficacy of plant-based therapies is to improve the stability and bioavailability of their bio-active ingredients. Phytosomes employ phospholipids as their active ingredients, and use their amphiphilic properties to solubilize and protect herbal extracts. The unique properties of phospholipids in drug delivery and their use in herbal medicines to improve bioavailability results in significantly enhanced health benefits. The introduction of phytosome nanotechnology can alter and revolutionize the current state of drug delivery. The goal of this review is to explain the application of phytosomes, their future prospects in drug delivery, and their advantages over conventional formulations.

关键词： Phytochemical Bioavailability Drug delivery system Phytosome Plant extracts

Engineering of oxygen vacancy and bismuth cluster assisted ultrathin Bi_(12)O_(17)Cl_(2)nanosheets with efficient and selective photoreduction of CO_(2)to CO

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Carbon Energy 2024年第4期6卷 1-11页

作者： Meili Guan Ni Lu Xuan Zhang Qiuwan Wang Jian Bao Guiye Chen Hao Yu Huaming Li Jiexiang Xia Xuezhong Gong College of Chemical and Biological Engineering Shandong University of Science and TechnologyQingdaoShandongChina institute for Energy research Jiangsu UniversityZhenjiangJiangsuChina national Center of International Joint research for Hybrid materials Technology Institute of Hybrid MaterialsCollege of Materials Science andEngineeringNational Base of International Science and Technology Cooperation on Hybrid MaterialsQingdao UniversityQingdaoShandongChina

The photocatalytic conversion of CO_(2)into solar‐powered fuels is viewed as a forward‐looking strategy to address energy scarcity and global *** work demonstrated the selective photoreduction of CO_(2)to CO using ultrathin Bi_(12)O_(17)Cl_(2)nanosheets decorated with hydrothermally synthesized bismuth clusters and oxygen vacancies(OVs).The characterizations revealed that the coexistences of OVs and Bi clusters generated in situ contributed to the high efficiency of CO_(2)–CO conversion(64.3μmol g^(−1)h^(−1))and perfect *** OVs on the facet(001)of the ultrathin Bi_(12)O_(17)Cl_(2)nanosheets serve as sites for CO_(2)adsorption and activation sites,capturing photoexcited electrons and prolonging light absorption due to defect *** addition,the Bi‐cluster generated in situ offers the ability to trap holes and the surface plasmonic resonance *** study offers great potential for the construction of semiconductor hybrids as multiphotocatalysts,capable of being used for the elimination and conversion of CO_(2)in terms of energy and environment.

关键词： Bi cluster Bi_(12)O_(17)Cl_(2)nanosheet oxygen vacancy photocatalytic CO_(2)reduction

Effect of Nb-content on the corrosion resistance of Co-free high entropy alloys in chloride environment

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Tungsten 2024年第4期6卷 778-793页

作者： Peng-Fei Dai Yang Zhang Sergey Rogozhkin Ji-Hong Han Shu-Wen Li Zhong-Wu Zhang Key Laboratory of Superlight materials and Surface Technology Ministry of Education College of Materials Science and Chemical Engineering Harbin Engineering University national research Nuclear University “MEPh I” national research Center “Kurchatov institute”

This study investigated the effect of Nb-content on the corrosion behavior of the Al7Cr20Fe35-xNi35Mo3Nbx（x=0,1 and 2）high-entropy alloys in a *** results indicated that only the face centered cubic phase existed in the NbO and Nbl alloys,while the emergence of Laves phase was observed when Nb-content reached 2 at.%.The NbO and Nb1alloys exhibited pitting corrosion,while the NiAl-rich phase experienced localized preferential corrosion in the Nb2 *** electrochemical results revealed that the corrosion current density of the Nbx（x=0,1 and 2） alloys fell within the range of 10-8-10-7A·cm-2,with a pitting corrosion potential exceeding 700 ***,the Nb1 alloy exhibited the most impressive corrosion resistance,as its corrosion current density(7 × 10-8A·cm-2) was merely half that of 316LN stainless *** is attributed to its rapid passivation process,resulting in the development of a protective film characterized by an increased Cr2O3/Al2O3+Cr（OH）*** study highlighted that the addition of Nb contributed to gram refinement,decreased corrosion current density,and elevated pitting potential,favoring passivation and improving corrosion ***,excessive Nb-content resulted in the emergence of the Laves phase,inducing galvanic corrosion and diminishing resistance to corrosion.

关键词： Corrosion High entropy alloys Microstructure Niobium Passive film