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Carbonaceous nanomaterials, such as fullerene C60, carbon nanotubes, and their functionalized derivatives have been demonstrated to possess high sorption capacity for organic and heavy metal contaminants, indicating a potential for remediation application. The actual application of these nanomaterials, however, is often hindered by the high cost of materials and the limited understanding of their mobility in porous media. In this work, carbon nano-onions (CNOs), a relatively new addition to the carbonaceous nanomaterials, were synthesized in a cost-effective way using a laser-assisted combustion synthesis process, and carefully characterized for their potential remediation application. Surface oxidized CNOs possessed 10 times higher sorption capacity than C60 for heavy metal ion contaminants including Pb2+, Cu2+, Cd2+, Ni2+, and Zn2+. CNOs aqueous suspension can be very stable in NaCl solution at ionic strength up to 30?mM and CaCl2 solution at ionic strength up to 4?mM CaCl2 when pH ranged from 5 to 9, which are consistent with environmentally relevant conditions. Interactions of CNOs with iron oxide and silica surfaces under favorable condition were found to be electrostatic in origin. Mobility of CNOs in quartz sands was controlled by electrolyte type and concentration. Approximately 4.4, 25.1, and 92.5?% of injected CNO mass were retained in the sand column in ultrapure water, 1?mM?NaCl, and 1?mM CaCl2 solutions, respectively. 相似文献
94.
In this work, we describe a set of coordinates on the PU(2,1)-representation variety of the fundamental group of an oriented
punctured surface Σ with negative Euler characteristic. The main technical tool we use is a set of geometric invariants of
a triple of flags in the complex hyperbolic plane
H2\mathbb C{\bf H^2_{\mathbb {C}}} . We establish a bijection between a set of decorations of an ideal triangulation of Σ and a subset of the PU(2,1)-representation
variety of π
1(Σ). 相似文献
95.
96.
M. Beck U. Vogt I. Will A. Liero H. Stiel W. Sandner T. Wilhein 《Optics Communications》2001,190(1-6):317-326
We describe the development of a table top soft X-ray source based on a laser produced plasma. The plasma is produced by a Nd:YLF pulse-train laser which delivers pulse trains of up to 400 pulses each of about 25 ps duration. Number and energy of the micropulses are fully computer controlled adjustable for an optimum interaction with a rotating solid target. Spectral, spatial and temporal characteristics of the X-ray emission from Mylar and copper targets have been studied. A calibrated back-illuminated CCD camera together with a slit grating spectrograph were utilized for the measurement of the absolute soft X-ray photon fluxes. The temporal measurements were performed using a streak camera while the plasma size was measured with a zone plate. An application of the system in a X-ray absorption experiment is shown. The advantages of the system in view of possible optical pump and soft X-ray probe experiments will be discussed. 相似文献
97.
Liam McElroy Mark Nieuwenhuyzen Graham C. Saunders 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):678-679
The title molecule, [Mo{P(C6H5)2(C6H4F)}(HNC5H10)(CO)4] or [Mo(C18H14FP)(C5H11N)(CO)4], has irregular octahedral geometry about the Mo atom. The molecules form a complicated hydrogen‐bonded network comprising C—H?O, C—H?F and C—H?π hydrogen bonds and π–π interactions. The C—H?π and π–π interactions form chains containing C—H?π/π–π dimers linked via C—H?π interactions and the chains are linked into a three‐dimensional network via C—H?O and C—H?F hydrogen bonds. 相似文献
98.
Hisham Ali Jawad Ahmad Zakwan Jaroucheh Pavlos Papadopoulos Nikolaos Pitropakis Owen Lo Will Abramson William J. Buchanan 《Entropy (Basel, Switzerland)》2022,24(10)
Historically, threat information sharing has relied on manual modelling and centralised network systems, which can be inefficient, insecure, and prone to errors. Alternatively, private blockchains are now widely used to address these issues and improve overall organisational security. An organisation’s vulnerabilities to attacks might change over time. It is utterly important to find a balance among a current threat, the potential countermeasures, their consequences and costs, and the estimation of the overall risk that this provides to the organisation. For enhancing organisational security and automation, applying threat intelligence technology is critical for detecting, classifying, analysing, and sharing new cyberattack tactics. Trusted partner organisations can then share newly identified threats to improve their defensive capabilities against unknown attacks. On this basis, organisations can help reduce the risk of a cyberattack by providing access to past and current cybersecurity events through blockchain smart contracts and the Interplanetary File System (IPFS). The suggested combination of technologies can make organisational systems more reliable and secure, improving system automation and data quality. This paper outlines a privacy-preserving mechanism for threat information sharing in a trusted way. It proposes a reliable and secure architecture for data automation, quality, and traceability based on the Hyperledger Fabric private-permissioned distributed ledger technology and the MITRE ATT&CK threat intelligence framework. This methodology can also be applied to combat intellectual property theft and industrial espionage. 相似文献
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100.
4-Hydroxy-2-alkenyldiphenylphosphine oxides, prepared by a phosphorus-controlled allylic rearrangement, give dianions and hence α-hydroxydienes (substituted penta-2,4-dienols) by the Horner-Wittig reaction. 相似文献