45,826 research outputs found
New performing GC columns with unmatched separation capabilities
No full textGas chromatography (GC) is widely used for qualitative and quantitative analysis in numerous fields, such as petroleum, chemical industry, agriculture, environmental protection, medicine, and so on, due to its high
versatility, high selectivity, simplicity of use, analysis speed, and low sample consumption. The column is the heart of a GC instrumentation, which allows the analyte separation and their recognition and quantification. Commercial columns do not always allow a complete peak separation when compounds (i.e., isomers) are very
similar in molecular weight, polarity, and vapor pressure. The choice of the correct stationary phase, with high selectivity towards target analytes, is the key to obtaining the required chromatographic separation and the subsequent qualitative and quantitative analysis.
Considering the rapid polymer science development and the growing demand for new columns with
improved resolution capabilities, in this work novel stationary phases for capillary GC have been designed, synthesized, and characterized in terms of polarity range, resolution, column efficiency, thermal stability, filmforming properties, and support-deactivating capacity1-5. The separation features of these novel stationary phases allow high-resolution performances for a wide range of compounds, like aromatic anilines, xylenes, aromatic amines, halogenated benzenes, and aromatic aldehydes, with marked capabilities toward isomer separations.References:
[1] T. Sun, M. Ba, Y. Song, W. Li, Y. Zhang, Z. Cai, S. Hu, X. Liu, D. Nardiello, M. Quinto, Analytica Chimica Acta, 2024, 1291, art. no. 342221.
[2] T. Sun, R. Chen, Q. Huang, M. Ba, Z. Cai, H. Chen, Y. Qi, H. Chen, X. Liu, D. Nardiello, M. Quinto, Analytica
Chimica Acta, 2023, 1251, art. no. 340979.
[3] T. Sun, R. Chen, Q. Huang, M. Ba, Z. Cai, S. Hu, X. Liu, D. Nardiello, M. Quinto, ACS Applied Materials and Interfaces, 2022, 14 50, pp. 56132-56142
[4] R. Chen, Z. Cai, W. Li, Q. Huang, D. Nardiello, M. Quinto, X. Liu, S. Hu, T. Sun, Chemistry and Biodiversity, 2022,
19, art. no. e202200829
[5] Q. Huang, Z. Cai, R. Chen, W. Zhang, D. Nardiello, M. Quinto, X. Liu, S. Hu, T. Sun, Microchemical Journal, 2022,
183, art. no. 10808
INNOVATIVE PILLAR[6]ARENE-BASED STATIONARY PHASES FOR HIGH-RESOLUTION GAS CHROMATOGRAPHIC ANALYSES
No full textIn this work, the synthesis, fabrication, and characterization of new stationary phases based on pillar[6]arene derivative modified by long alkyl chains (P6A-C10) for high-resolution gas chromatographic (GC) analyses are reported. Pillar[n]arenes are a new class of macrocyclic hosts that can accommodate specific guests due to their highly symmetrical and rigid pillar architectures with π-electron rich cavities. Quantum chemistry calculations have been performed, showing a difference in non-covalent interactions with the P6A-C10 pillar framework, which leads to specific selectivity for aromatic compounds. The GC columns prepared with these innovative stationary phases exhibited a medium polarity, and good reproducibility for run-to-run, day-to-day, and column-to-column analyses [1], demonstrating great potential as new stationary phases in separation science. Furthermore, peculiar advantages are achieved if compared with the commercial HP-5, HP-35, DB-17, and PEG-20M columns, showing unmatched resolving capabilities toward chloroaniline, bromoaniline, iodoaniline, toluidine, and xylene isomers [2].
References:
1. Sun, T., Chen, R., Huang, Q., Ba, M., Cai, Z., Hu, S., Liu, X., Nardiello, D., & Quinto, M., ACS Appl. Mater. Interfaces 14 (2022) 56132−56142.
2. Sun, T., Chen, R., Huang, Q., Ba, M., Cai, Z., Chen, H., Qi, Y., Chen, H., Liu, X., Nardiello, D., & Quinto, M., Anal. Chim. Acta 1251 (2023) 340979
Guest editorial guided lightwaves for sensors and measurement systems: advanced techniques and applications
No full textThis IEEE/OSA Journal of Lightwave Technology special issue on \u201cGuided Lightwaves for Sensors & Measurement Systems: Advanced Techniques and Applications\u201d is organized by the IEEE Instrumentation and Measurement Society. It aims to highlight the advancement of guided lightwaves in applications to sensors, instrumentation and measurement. The special issue includes both comprehensive review articles and original technical contributions covering the rapid advancement of guided lightwaves in the applications to instrumentation and measurement. 18 invited papers and 22 contributed papers will be published in this issue. The authors are from universities, government labs and industries. We hope that this JLT Special Issue will provide an in-depth look at the topic areas and serve as a valuable reference for the current and future scientists, engineers, and technical applicators working in the related fields.Peer reviewed: YesNRC publication: Ye
A Formal Model of Semantic Web Service Ontology (WSMO) Execution
No full textSemantic Web Services have been one of the most significant research areas within the Semantic Web vision, and have been recognized as a promising technology that exhibits huge commercial potential. Current Semantic Web Service research focuses on defining models and languages for the semantic markup of all relevant aspects of services, which are accessible through a Web service interface. The Web Service Modelling Ontology (WSMO) is one of the most significant Semantic Web Service framework proposed to date. To support the standardization and tool support of WSMO, a formal semantics of the language is highly desirable. As there are a few variants of WSMO and it is still under development, the semantics of WSMO needs to be formally defined to facilitate easy reuse and future development. In this paper, we present a formal Object-Z semantics of WSMO. Different aspects of the language have been precisely defined within one unified framework. This model provides a formal unambiguous specification, which can be used to develop tools and facilitate future development
Does the Moon Always Fall Towards the Sun?
No full textIt is claimed in [1] that the Moon always falls towards the Sun? Can this be so? It suffices to suppose that the Earth’s orbit about the Sun, and the Moon’s orbit about the Earth, are both circular. 2 Solution The term “fall ” apparently means different things to different people. The usual convention is that an object is “falling ” (down) if its velocity is “downwards. ” However, some people consider that an object is “falling ” (down) if its acceleration is “downwards ” even when its velocity is “upwards.” In cylindrical coordinates (r, φ, z) the position vector r = r r̂+ z z ̂ has velocity vector v = r ̇ = r ̇ r̂+ rφ ̇ φ ̂ + z ̇ ẑ, (1) where r ̇ = d r/d t, etc., and acceleration vector a = r ̈ = (r ̈ − rφ̇2) r̂+ (rφ ̈ + 2ṙφ̇) φ ̂ + z ̈ ẑ, (2) Taking the Earth’s and Moon’s orbits to be circular relative to the Sun and Earth, with angular velocities Ω and ω, respectively, the distance r from the Sun to the Moon obeys r2 = r21 + r 2 2 + 2r1r2 cos[(ω −Ω)t], (3) where r1 is the radius of the Earth’s orbit, r2 < r1 is the radius of the Moon’s orbit, and the Moon is at its maximal distance from the Sun at time t = 0. The time derivative of eq. (3) is rr ̇ = −(ω − Ω)r1r2 sin[(ω − Ω)t]. (4) Thus, the radial velocity r ̇ r ̂ oscillates in sign and by the usual convention the Moon does not always fall towards the Sun. 2.1 Radial Acceleration The acceleration a of the Moon (whose position vector is r) follows from Newton’s law of gravitation (ignoring effects of other planets and stars) as a = −GMSun r2 r̂+ GMEarth rEarth − r |rEarth − r|3. (5) 1 Clearly the radial component of the acceleration is negative when the Moon is farthest from the Sun. When the Moon is closest to the Sun, ar = − GMSun (r1 − r2)2
Perspectives on Identity, Migration, and Displacement
No full textPerspectives on Identity, Migration, and Displacement -- edited by Steven Tötösy de Zepetnek, I-Chun Wang, and Hsiao-Yu Sun (Kaohsiung: National Sun Yat-sen University Press, 2010. ISBN 9789860235418 209 pages, bibliography, index) is a collection of articles about sociological and literary aspects of identity formation as a consequence of (im)migration. (Im)migration results in the problematics of assimilation and hybridity and in postcolonial scholarship, in particular, attention is paid to the concept of migration termed Creolization on the ground that cultural contact, cultural transmission, and cultural transformation result in the creation of new cultures. Copyright release by National Sun Yat-sen University to the authors 2013
ISOMER SEPARATIONS BY INNOVATIVE GAS CHROMATOGRAPHY STATIONARY PHASES
No full textThe chromatographic separation of aromatic amines and xylenes isomers represents a big issue in chemical and petroleum industries, owing to their high similarity in terms of molecular sizes, polarity, and boiling points: as a result, commercial columns very often do not allow their complete peak separation. For this reason, several typologies of materials with different structures and properties have been developed and proposed as gas chromatography stationary phases in recent years. Macrocycles and ionic liquid-based chain-typed copolymers have emerged, due to their special chromatographic selectivity and separation mechanisms, resulting from their three-dimensional structures and outstanding thermal stability. Very recently, innovative stationary phases based on functionalized calixarene-polyethylene glycol (C4A-mPEG) [1], and amphiphilic triblock copolymer bonded with benzimidazolium ionic liquid (TCP-Bim) [2] were designed, characterized, and used for GC separations of aromatic isomers. The separation features of the C4A-mPEG stationary phase, resulting from multiple molecular recognition processes with analytes, including π-π, H-bonding, dipole-dipole, and van der Waals interactions, allowed to obtain high-resolution performances for a wide range of compounds and their isomers, especially benzaldehydes, phenols, and anilines. Moreover, compared with 4-tertbutyl calix[4]arene (C4A) and polyethylene glycol (PEG) stationary phases, a higher resolving capability was also observed for the separation of toluidine and xylidine isomers. The separation capabilities of the TCP-Bim columns are attributable to different analyte-stationary phase interaction mechanisms, arising from the particular TCP-Bim structure that combines ionic liquid and copolymer peculiarities, showing stronger retention towards aromatic compounds. The high-resolution capabilities of the TCP-Bim column were also tested with different aliphatic cis-/trans-isomers; the excellent separation performances for analytes with very similar properties demonstrated the good potential of these innovative materials as new classes of stationary phases for high-resolution GC separations.
References:
1. Chen, R., Cai, Z., Li, W., Huang, Q., Nardiello, D., Quinto, M., Liu, X., Hu, S., & Sun, T., Chem. Biodiversity 19 (2022) e202200829.
2. Huang, Q., Cai, Z., Chen, R., Zhang, W., Nardiello, D., Quinto, M., Liu, X., Hu, S., & Sun, T., Microchemical Journal 183 (2022) 108084
Impact of active areas on electrical characteristics of TiO<sub>2</sub> based solid-state memristors
No full textGuest Editorial Neuro-Robotics Systems: Sensing, Cognition, Learning, and Control
No full textNeuro-robotics systems (NRSs) are the most advanced research in the field of robotics, promoting the seamless exchange of knowledge between neuroscience and robotics. Recent breakthroughs in human brain neuroscience could be applied to robots to improve their perception, cognition, learning, and control abilities, which even help to develop a brain for robots. A challenge of robotics research is to break through technical bottlenecks by the findings in neuroscience and make robots move more flexibly, have more intelligent perception and control, and communicate with humans more naturally. To address the challenge, this special issue focuses on the latest advances in the area of NRS, particularly, the research concentrating on human-like sensing, multimodal information fusion, cognition, learning, and control technology. The development of these technologies aims to bring innovations into robotics and NRSs
Quasi-steady three-degrees-of-freedom aerodynamic model of inclined/yawed prisms: Formulation and instability for galloping and static divergence
No full textIn this study, a generalized three-degree-of-freedom (3-DoF) analytical model is formulated to predict linear aerodynamic instabilities of a prism under quasi-steady (QS) conditions. The prism is assumed to possess a generic cross-section exposed to turbulent wind flow. The 3-DoFs encompass two orthogonal horizontal directions and rotation about the prism body axis. Inertial coupling is considered to account for the non-coincidence of the mass center and the rotation center. The aerodynamic force coefficients—drag, lift, and moment—depend on the Reynolds number based on relative flow velocity, angle of attack, and the angle between the wind and the cable. Aerodynamic forces are linearized with respect to the static equilibrium configuration and mean wind velocity. Routh-Hurwitz and Liénard and Chipart criteria are used in the eigenvalue problem, yielding an analytical solution for instabilities in galloping and static divergence types. Additionally, the minimum structural damping and stiffness required to prevent these instabilities are numerically determined. The proposed 3-DoF instability model is subsequently applied to a conductor with ice accretion and a full-scale dry inclined cable. In comparison to existing models, the developed model demonstrates superior prediction accuracy for unstable regions compared with results in wind tunnel tests
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