More than a decade after Phillips' first published work this article reviews recent developments in comprehensive two-dimensional gas chromatography (GC x GC). Special attention is devoted to the further development and diversity of modulation devices. These include heated sweepers, cryofocused modulators, and a variety of diaphragm valve-switching strategies. It is demonstrated that all modulation approaches can be very well suited to GC x GC, depending on the particular application. Diaphragm-valve modulation is very powerful for volatile organic compounds. Slotted heater and cryofocused modulation are preferred for samples that contain non-volatile components. Applications ranging from petroleum to environmental and biological samples are illustrated. Extension of the technique to GC x GC-mass spectrometry (MS) is also discussed and trends for future research activity are pointed out.
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http://dx.doi.org/10.1007/s00216-002-1318-7 | DOI Listing |
J Phys Chem Lett
January 2025
Department of Materials Science & Engineering, City University of Hong Kong, Kowloon, Hong Kong.
Despite numerous studies of water structures at the two-dimensional water-solid interfaces, much less is known about the phase behaviors of water at the one-dimensional (1D) liquid-solid interface. In this work, the 1D interfacial water phase behavior on the outer surface of carbon nanotube-like (CNT-like) models is studied by tuning the Lennard-Jones potential parameter ε of the surface atoms at various temperatures. Extensive molecular dynamics simulations show that ice nanotubes (INTs) can be spontaneously formed on CNT-like model surfaces without nanoconfinement.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Environmental Theoretical Chemistry, School of Environment, South China Normal University, Guangzhou 510006, China.
Two-dimensional (2D) electronic spectra of the phenylene ethynylene dendrimer with 2-ring and 3-ring branches were evaluated by combining the on-the-fly trajectory surface hopping nonadiabatic dynamics and the doorway-window simulation protocol. The ground state bleach (GSB), stimulated emission (SE), and excited-state absorption (ESA) contributions to the 2D signal were obtained and carefully analyzed. The results demonstrate that the ultrafast intramolecular nonadiabatic excited-state energy transfer (EET) from the 2-ring to the 3-ring units is comprehensively characterized by the SE and ESA signals.
View Article and Find Full Text PDFOrthod Fr
January 2025
Laboratoire Forme et Croissance du Crâne, Institut Imagine, 24 boulevard du Montparnasse, 75015 Paris, France
Introduction: Facial asymmetry, present in all human faces at varying degrees, plays a critical role in clinical fields such as orthodontics, orthognathic and plastic surgeries, and craniofacial reconstruction. Accurate quantification of facial asymmetry is essential for diagnosis, treatment planning, and post-surgical evaluation.
Material And Methods: This article examines contemporary methods for quantifying facial asymmetry, including two-dimensional (2D) and three-dimensional (3D) landmark-based approaches, surface curvature analysis, and advanced image-based techniques.
Nanoscale
January 2025
Institute of Energy Power Innovation, North China Electric Power University, 2 Benigno Road, Beijing 102206, P. R. China.
The electrocatalytic carbon dioxide reduction reaction (CORR) is an attractive method for converting atmospheric CO into value-added chemicals and fuels. In order to overcome the low efficiency and durability that hinder its practical application, a significant amount of research has been dedicated to designing novel catalysts at the nanoscale and even the atomic scale. Two-dimensional (2D) monolayer materials inherit the merits of both 2D materials and single-atom materials.
View Article and Find Full Text PDFNat Mater
January 2025
School of Physics, Zhejiang University, Hangzhou, China.
In ordered magnets, the elementary excitations are spin waves (magnons), which obey Bose-Einstein statistics. Similarly to Cooper pairs in superconductors, magnons can be paired into bound states under attractive interactions. The Zeeman coupling to a magnetic field is able to tune the particle density through a quantum critical point, beyond which a 'hidden order' is predicted to exist.
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