The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle ...The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle Devonian, and its geological occurrence is consistent with the wall rocks. A large number of spheroidal pyrite aggregates are found unevenly distributed in the ores. The spheroidal aggregates are made up of kernels and concentric rings. The kernels are composed of approximately epigranular pyrite nanocrystals, while the rings are composed of accumulated pyrite microcrystals growing along the radial direction. The spheroidal pyrite aggregate and its outer zones can be divided into five areas（A–E）. The results of electron probe micro analysis（EPMA） show that from the zone A1 to B, Co/Ni 〈1, the sum of Co and Ni is 0.08%–0.26%, S/Fe increases from 2.06 to 2.15. While from the zone C to E, Ni cannot be detected and S/Fe decreases from 2.22 to 2.08. Powder X-ray diffraction（XRD） analysis in the micro zone shows obvious crystalline characteristics in the aggregates. Moving from the inside outwards, the maximum diffraction peak intensity of the（111） and（220） crystal planes of pyrite increases, and the crystallinity improves. The degree of change in the（111） plane is the most prominent. Considering the theory of crystal growth along with the geologic features of the depositional environment where the spheroidal pyrite aggregates developed, we confirm that the spheroidal aggregates are the result of nano-micro crystalline gathering and growth occurring by the following sequence of processes：nano-crystalline nucleation and growth, gathering into a ball, oriented growth of microcrystals, continuous accumulation, and adjustment of grain boundaries. The formation of the spheroidal pyrite aggregates in the late Qiziqiao Formation of the Middle Devonian occurred in a neutral to weak alkaline and reductive sedimentary environment in the normal oxygen-rich shallowwater carbonate platform edge. The variations in the S/Fe ratio and crystallisation characteristics indicate that during pyrite crystal growth, the sulphur fugacity was high locally and rose constantly, the degree of supersaturation decreased locally and the growth environment was stable relatively.展开更多
Copyright Information For copyright regulations and license agreement, please go to http://springeropen.com/about/copyright Open Access The articles published in this journal are distributed under the terms of the Cre...Copyright Information For copyright regulations and license agreement, please go to http://springeropen.com/about/copyright Open Access The articles published in this journal are distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s)and source are credited.展开更多
Copyright Information For copyright regulations and license agreement,please go to www.springeropen.com/about/copyright Open Access The articles published in this journal are distributed under the terms of the Creativ...Copyright Information For copyright regulations and license agreement,please go to www.springeropen.com/about/copyright Open Access The articles published in this journal are distributed under the terms of the Creative Commons Attribution License which permits any use,distribution,and reproduction in any medium,provided the original author(s)展开更多
The following transfer agreement must be signed and send the scanned file to the journal of Nano-Micro Letters Editorial Office(E-mail:editor@nmletters.org)before the manuscript can be published.For questions and furt...The following transfer agreement must be signed and send the scanned file to the journal of Nano-Micro Letters Editorial Office(E-mail:editor@nmletters.org)before the manuscript can be published.For questions and further information about the journal practices regarding copyright,please email:editor@nmletters.org.展开更多
With the widespread adoption of communication technology,the potential hazards of electromagnetic(EM)radiation to human health and electronic devices operation have also emerged.Therefore,microwave absorption(MA)mater...With the widespread adoption of communication technology,the potential hazards of electromagnetic(EM)radiation to human health and electronic devices operation have also emerged.Therefore,microwave absorption(MA)materials are becoming increasingly vital in the current electronic information age.Currently,extensive researches have been conducted on the MA mechanisms and optimized strategies,leading to significant advancements in improving MA performance.However,there is a lack of systematic summary of various innovative engineering strategies from nano-micro scale to metamaterial.Typically,nano-micro engineering techniques readily introduce heterointerfaces,components,or defects,etc.to boost dielectric loss and/or magnetic loss.And macroscopic strategy focuses on crafting more porous three-dimensional structures(foams,aerogels,films,etc.),which are beneficial for fine-tuning intrinsic impedance and triggering multiple reflections/scattering of EM wave(EMW).While metamaterial design featuring periodic layouts and sub-wavelength scales can also lead to energy loss via EMW resonances.Hence,in this review,we aim to provide a detailed overview of various engineering strategies for enhancing MA performance from nano-micro engineering to macroscopic strategies to metamaterial design.Furthermore,we elaborate the present challenges faced by MA technology and discuss potential future development opportunities and trends.It is our hope that this paper will offer insights and direction for the ongoing improvement of MA performance and achieving practical applications.展开更多
基金granted by the National Natural Science Foundation of China (Grant No. 41172047, 41272062)the Open Fund of the State Key Laboratory of Ore Deposit Geochemistry (Institute of Geochemistry, Chinese Academy of Sciences, Guiyang) (Grant No. 201308)
文摘The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle Devonian, and its geological occurrence is consistent with the wall rocks. A large number of spheroidal pyrite aggregates are found unevenly distributed in the ores. The spheroidal aggregates are made up of kernels and concentric rings. The kernels are composed of approximately epigranular pyrite nanocrystals, while the rings are composed of accumulated pyrite microcrystals growing along the radial direction. The spheroidal pyrite aggregate and its outer zones can be divided into five areas（A–E）. The results of electron probe micro analysis（EPMA） show that from the zone A1 to B, Co/Ni 〈1, the sum of Co and Ni is 0.08%–0.26%, S/Fe increases from 2.06 to 2.15. While from the zone C to E, Ni cannot be detected and S/Fe decreases from 2.22 to 2.08. Powder X-ray diffraction（XRD） analysis in the micro zone shows obvious crystalline characteristics in the aggregates. Moving from the inside outwards, the maximum diffraction peak intensity of the（111） and（220） crystal planes of pyrite increases, and the crystallinity improves. The degree of change in the（111） plane is the most prominent. Considering the theory of crystal growth along with the geologic features of the depositional environment where the spheroidal pyrite aggregates developed, we confirm that the spheroidal aggregates are the result of nano-micro crystalline gathering and growth occurring by the following sequence of processes：nano-crystalline nucleation and growth, gathering into a ball, oriented growth of microcrystals, continuous accumulation, and adjustment of grain boundaries. The formation of the spheroidal pyrite aggregates in the late Qiziqiao Formation of the Middle Devonian occurred in a neutral to weak alkaline and reductive sedimentary environment in the normal oxygen-rich shallowwater carbonate platform edge. The variations in the S/Fe ratio and crystallisation characteristics indicate that during pyrite crystal growth, the sulphur fugacity was high locally and rose constantly, the degree of supersaturation decreased locally and the growth environment was stable relatively.
文摘Copyright Information For copyright regulations and license agreement, please go to http://springeropen.com/about/copyright Open Access The articles published in this journal are distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s)and source are credited.
文摘Copyright Information For copyright regulations and license agreement,please go to www.springeropen.com/about/copyright Open Access The articles published in this journal are distributed under the terms of the Creative Commons Attribution License which permits any use,distribution,and reproduction in any medium,provided the original author(s)
文摘The following transfer agreement must be signed and send the scanned file to the journal of Nano-Micro Letters Editorial Office(E-mail:editor@nmletters.org)before the manuscript can be published.For questions and further information about the journal practices regarding copyright,please email:editor@nmletters.org.
基金supported by Innovation Group of Guizhou University(No.[2024]08)Platform of Science and Technology and Talent Team Plan of Guizhou province(No.GCC[2023]007)Fok Ying Tung Education Foundation(No.171095)for financial support.
文摘With the widespread adoption of communication technology,the potential hazards of electromagnetic(EM)radiation to human health and electronic devices operation have also emerged.Therefore,microwave absorption(MA)materials are becoming increasingly vital in the current electronic information age.Currently,extensive researches have been conducted on the MA mechanisms and optimized strategies,leading to significant advancements in improving MA performance.However,there is a lack of systematic summary of various innovative engineering strategies from nano-micro scale to metamaterial.Typically,nano-micro engineering techniques readily introduce heterointerfaces,components,or defects,etc.to boost dielectric loss and/or magnetic loss.And macroscopic strategy focuses on crafting more porous three-dimensional structures(foams,aerogels,films,etc.),which are beneficial for fine-tuning intrinsic impedance and triggering multiple reflections/scattering of EM wave(EMW).While metamaterial design featuring periodic layouts and sub-wavelength scales can also lead to energy loss via EMW resonances.Hence,in this review,we aim to provide a detailed overview of various engineering strategies for enhancing MA performance from nano-micro engineering to macroscopic strategies to metamaterial design.Furthermore,we elaborate the present challenges faced by MA technology and discuss potential future development opportunities and trends.It is our hope that this paper will offer insights and direction for the ongoing improvement of MA performance and achieving practical applications.
