40 research outputs found
Uncovering temperature-tempted coordination of inclusions within ultra-high-strength-steel via in-situ spectro-microscopy
Funding Information: Authors acknowledge Academy of Finland grant #311934 and Kvantum Institute, University of Oulu (Project CLEAN2STEEL) for the financial support. We also thank the crew of the MAX IV laboratory for their support during the beamtime operation. Authors would like to thank Mr. Tun Nyo for the assistance in sample preparation for SEM and X-PEEM, Mr. Jaakko Hannula for insightful discussions, and the Centre for Material Analysis, University of Oulu is also acknowledged for in-house characterizations. Publisher Copyright: Β© 2022 The Author(s)Despite the common challenge of investigating non-metallic inclusions within ultra-high-strength-steel (UHSS) at sub-micrometer scale via conventional methods, probing nitride inclusions at elevated temperatures is vital for guiding steelβ performance. Herein, an in-situ spectro-microscopic determination using advanced Synchrotron X-ray absorption spectroscopy (XAS) coupled with photoelectron emission microscopy (PEEM) is employed to explore the local structure and electronic properties of selective h-boron nitride (h-BN) containing inclusions (A1 and A2) embedded within steel matrix. While the variation in the relative intensity of Οβ/Οβ excitonic peaks at spatially different locations refers to the polarization and or thickness effects. Several minute features observed in the 192β195 eV energy range show oxygen (O) substituted nitrogen (N) defects (ON,2N,3N), which are more dominant in A2 inclusion. The observed dominance further explains the relatively high intense Οβ peak in A2 due to increased localization. Weak shoulder on the left side of Οβ peak in both room and high-temperature XAS spectra is ascribed to the interaction between h-BN and the local environment, such as Ca-based inclusion or steel matrix. Defects are commonly found in h-BN, and precise identification of the same is vital as they affect the overall physical, chemical, and mechanical properties. Moreover, significant changes in high-temperature B K-edge XAS spectra, such as relative intensity of Οβ/Οβ excitonic peaks at the same location and reduced intensity of defects, suggest the adjusting nature of BN inclusion, complicating their precise prediction and control towards clean steel production.Peer reviewe
Unraveling compensation between electron transfer and strain in Ni-Ag-MoS2 photocatalyst
Despite the boom in catalytic response via constructing interfaces, understanding interfacesβ interaction in heterostructures is still a paradox. In this work, the interaction of Ni with MoS2 in Ni-Ag-MoS2 heterostructure are unveiled through synchrotron X-PEEM and what\u27s more, the missing interaction mechanism at the Ag-MoS2 interface is probed via Raman mapping. The observed competition between the downshift of the E2g1 and A1g modes due to charge carrier injection and the upshift of the E2g1 and A1g modes due to compressive strain during reverse laser power experiment is assigned to the non-uniform growth of Ag nanoparticles, their intimate contact with MoS2, and Ag intercalated layered MoS2. The substantial improvement of the H2 yield of the Ni-Ag-MoS2 (βΌ55 ΞΌmol hβ1 gβ1) over the pristine MoS2 and the binary Ag-MoS2 evidence successful bonding of Ni, Ag and MoS2. This study highlights the importance of considering both electronic coupling and strain to optically tune electromechanical properties of MoS2
Sensitive and selective detection of DNA fragments associated with Ganoderma boninense by DNA-nanoparticle conjugate hybridisation
From Springer Nature via Jisc Publications RouterHistory: received 2020-05-04, accepted 2020-07-05, registration 2020-07-05, pub-electronic 2020-07-20, online 2020-07-20, pub-print 2020-10Publication status: PublishedFunder: Newton Fund; doi: http://dx.doi.org/10.13039/100010897; Grant(s): British Council 216196834Funder: Engineering and Physical Sciences Research Council; doi: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/K024485/1Funder: Higher Education Funding Council for England; doi: http://dx.doi.org/10.13039/100011722; Grant(s): N8 Agrifood NetworkAbstract: A colourimetric assay for the detection of DNA fragments associated with the oil palm pathogen Ganoderma boninense and other fungi DNA is reported. The assay is based on the aggregation of DNA-nanoparticle conjugates in the presence of complementary DNA from the target organism. Here, various designs of DNA-nanoparticle conjugates were evaluated, and it was found that the best design gave a visually observable colour change with as little as 2 pmol of double-stranded DNA analyte even in the presence of a large excess of a mixture of non-complementary DNA. Overall, this label-free system is rapid, sensitive, selective, simple in design, and easy to carry out. It does not require specialist equipment or specialist training for the interpretation of the results, and therefore has the potential to be deployed for agricultural diagnostics in the field. Graphic abstract: Development of a colourimetric assay based on DNA-nanoparticle conjugates for the oil palm pathogen Ganoderma boninense
Unveiling nano-scaled chemical inhomogeneity impacts on corrosion of Ce-modified 2507 super-duplex stainless steels
The widely used stainless steels and their deformed variants are anticorrosive in ambient conditions due to passivation layers composed of chromium oxides. Conventionally, corrosion and erosion of the steels are attributed to the breakdown of such layers but seldomly to the origin that depends on surface heterogeneity at the microscopic level. In this work, the nanometer-scaled chemical heterogeneity at the surface unveiled via spectro-microscopy and chemometric analysis unexpectedly dominates the breakdown and corrosion behavior of the cold-rolled Ce-modified 2507 super-duplex stainless steels (SDSS) over its hot-deformed counterpart. Though relatively uniformly covered by a native Cr2O3 layer revealed by X-ray photoemission electron microscopy, the cold-rolled SDSS behaved poorly in passivity because of locally distributed Fe3+ rich nano-islands over the Fe/Cr oxide layer. This atomic-level knowledge provides a deep understanding of corrosion of stainless steel and is expected to benefit corrosion controls of similar high-alloyed metals
Ayurvedic ways to treat lung disoders
Is discribed information about herbal Ayurvedic medicines in respiratory disoders.ΠΊΠ°ΡΠ΅Π΄ΡΠ° ΠΏΡΠΎΠΏΠ΅Π΄Π΅Π²ΡΠΈΠΊΠΈ Π²Π½ΡΡΡΡΡΠ½ΡΡ
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