Article
Thermodynamics
Yuxiang Zhu, Chong-Wen Zhou, Alexander A. Konnov
Summary: In this study, the reaction kinetics of hydrogen-abstraction reactions from methoxymethanol by various radicals were investigated using high-level ab initio calculations. It was found that the H-abstraction reactions from the secondary carbon atom of methoxymethanol are favored pathways. Different radicals have different rate constants for hydrogen-abstraction reactions at different temperatures.
COMBUSTION AND FLAME
(2021)
Article
Engineering, Electrical & Electronic
Maria Allers, Andre Ahrens, Moritz Hitzemann, Henrike Bock, Thomas Wolf, Jorg Radunz, Fabian Meyer, Frank Wilsenack, Stefan Zimmermann, Arne Ficks
Summary: Using unmanned aerial vehicles (UAVs) equipped with gas detectors enables rapid exploration of contaminated areas and accurate detection and identification of chemical agents, providing a reliable assessment of risks and appropriate protection for first responders. However, UAVs have limitations in payload, operational range, and power requirements, posing significant technical challenges in choosing suitable gas sensors. This study presents a mobile ion mobility spectrometer (IMS) designed for UAV operation, with a closed gas loop, high-performance driver electronics, and wireless data transmission capabilities.
IEEE SENSORS JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Hiroki Hayashi, Satoshi Maeda, Tsuyoshi Mita
Summary: This article introduces the application of quantum chemical calculations in the development of synthetic methodologies. It can be used to analyze the reaction mechanisms of developed reactions and predict unknown reactions. The use of computational methods allows researchers to explore unknown reactions, catalysts, and synthetic routes more effectively before conducting time-consuming and costly experimental investigations.
Article
Chemistry, Multidisciplinary
Hiroki Hayashi, Satoshi Maeda, Tsuyoshi Mita
Summary: Quantum chemical calculations play a crucial role in the development of synthetic methodologies by analyzing reaction mechanisms and predicting unknown reactions. They drive the discovery of new methodologies through efficient computation, saving time and costs compared to experimental investigations, and enable the exploration of synthetic routes to complex molecules and catalyst design.
Article
Biochemical Research Methods
Alexander Haack, Christoph Schaefer, Stefan Zimmermann, W. Scott Hopkins
Summary: Ion mobility spectrometry is widely used in analytical chemistry, either as a stand-alone technique or coupled to mass spectrometry. Ions in the gas phase tend to form loosely bound clusters with surrounding solvent vapors, artificially increasing the collisional cross section and the mass of the ion. This, in turn, affects ion mobility and influences separation. Computational models have been developed to describe clustering as a function of various factors, but modeling ion mobility under high electrical field strengths remains a challenge. In this study, a first-principles model is validated by comparing its predictions with direct measurements, and the detailed information gained from the modeling provides important insights into cluster dynamics and interpretation of ion mobility spectra.
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
(2023)
Article
Chemistry, Multidisciplinary
S. Lathifa Banu, Vasu Veerapandy, Helmer Fjellvag, Ponniah Vajeeston
Summary: The relative stability of 11 different MoSe2 polymorphs is investigated using first-principles calculations based on density functional theory. Among the polymorphs, 1H, 2H, 2T, and 3Hb are predicted to be stable, while 4T and 3Ha are considered to be under a metastable condition. The stability analysis is supported by the calculation of mechanical and dynamical properties, as well as spectroscopic analysis using IR and Raman spectra.
Article
Computer Science, Interdisciplinary Applications
Maximilian Cohen, Dionisios G. Vlachos
Summary: The CKBIT Python software library enables users to implement Bayesian inference techniques for kinetic parameter estimation and uncertainty quantification. It leverages functionalities of other open source Python packages, offering simplified implementation through minimal user-required coding and straightforward Excel input files. The program provides various estimation options for activation energies, reaction orders, and pre-exponential terms from chemical reaction data.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Chemistry, Analytical
Chong Zhang, Kaitai Guo, Jiyao Wang, Tian Wang, Xiaohao Wang, Kai Ni
Summary: This study investigates the influence of electric field on the sensitivity of ion mobility spectrometry (IMS) and proposes an optimized design to enhance sensitivity. Experimental results demonstrate a significant improvement in the signal-to-noise ratio of DMMP dimer peak with the new design.
SENSORS AND ACTUATORS B-CHEMICAL
(2022)
Article
Instruments & Instrumentation
D. Atanasov, F. Cresto, L. Nies, M. Pomorski, M. Versteegen, P. Alfaurt, V. Araujo-Escalona, P. Ascher, B. Blank, L. Daudin, D. Guillet, X. Flechard, J. Ha, A. Husson, M. Gerbaux, J. Giovinazzo, S. Grevy, T. Kurtukian-Nieto, L. Leterrier, R. Lica, E. Lienard, C. Mihai, C. Neacsu, A. Ortega-Moral, G. Pascovici, M. Roche, N. Severijns, S. Vanlangendonck, A. Welker, D. Zakoucky
Summary: The article discusses the Weak Interaction Studies with 32Ar Decay (WISArD) experiment, which aims to extend the limits on scalar and tensor currents in the weak interaction and search for physics beyond the Standard Model. The evaluation of these limits relies on measuring the proton energy in beta-delayed proton emission, and the method tries to improve previous studies by considering positron-proton coincidences. Simulations were used to optimize the ion beam transport efficiency and validate proof-of-principle results obtained in November 2018. Upgrades are ongoing to improve the overall performance of the setup.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
(2023)
Article
Chemistry, Physical
Takefumi Handa, Akira Terasaki
Summary: We studied the spatial distribution of ions in a linear multipole radio-frequency ion trap using SIMION software for ion-trajecotry simulation. By considering the effects of space charge and ion-buffer He collisions, we reproduced the experimental observation of a ring profile of ion distribution in a linear octopole trap at high ion density. The simulation also showed that the ion distribution profile depends on the number of stored ions and the temperature of the buffer He gas. For a quadrupole trap, the ion distribution was observed to be located around the central axis of the trap, and the influence of electrode structure was discussed.
Article
Biochemical Research Methods
Andre Ahrens, Stefan Zimmermann
Summary: Ion mobility spectrometers are widely used in various applications due to their fast response times and high sensitivity, but can face challenges when dealing with gas mixtures. A miniaturized drift tube IMS coupled with a compact gas chromatograph is proposed to address this issue, reducing chemical cross sensitivities caused by competing gas-phase ionization processes through pre-separation.
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
(2021)
Article
Thermodynamics
Jie-Yao Lyu, Qiren Zhu, Xin Bai, Xuan Ren, Jing Li, Dongping Chen, Vitaly G. Kiselev, Yang Li, Wenming Yang
Summary: In this study, a detailed chemical kinetic mechanism consisting of 38 species and 131 reactions was developed to describe the initial decomposition process of FOX-7. The results showed that the H-atom transfer to the beta carbon atom followed by the nitro group elimination dominates the initial decomposition. This work provides quantitative predictions of the reaction pathways of gas-phase FOX-7 initial decomposition and serves as a foundation for the development of a fully detailed combustion kinetic mechanism for FOX-7.
COMBUSTION AND FLAME
(2023)
Article
Multidisciplinary Sciences
Yong Li, He Huang, Kai Zhang, Mi Hou, Fuqian Yang
Summary: This study investigates the influence of lithium trapping on mechanical stress in batteries and analyzes the changes in chemical stress under different lithium trapping scenarios. The results show that a constant concentration of trapped lithium increases chemical stress, while an inhomogeneous distribution of trapped lithium decreases chemical stress. These findings provide a foundation for mitigating lithium trapping and improving battery performance.
Article
Chemistry, Multidisciplinary
Dohyeong Kwon, Sung-Joon Park, Jaewoon Lee, Sangeon Park, Seung-Ho Yu, Duho Kim
Summary: An intriguing mechanism for enabling fast Na kinetics during oxygen redox (OR) is proposed to produce high-power-density cathodes for sodium-ion batteries based on the P2-type oxide models Na-2/3[Mn6/9Ni3/9]O-2 (NMNO) and Na-2/3[Ti1/9Mn5/9Ni3/9]O-2 (NTMNO) using the potential pillar effect. The NTMNO interlayer distance moderately decreases upon charging with oxygen oxidation, whereas that of NMNO decreases at a much faster rate. Fundamental electrochemical experiments clearly indicate that the Ti doping of the bare material significantly improves its rate capability during OR, and detailed electrochemical and structural analyses show much faster Na kinetics for NTMNO than for NMNO. A systematic comparison of the two cathode oxides based on experiments and first-principles calculations establishes the potential pillar concept of not only improving the sluggish Na kinetics upon OR reaction but also harnessing the full potential of the anionic redox for high-power-density SIBs.
Article
Biochemical Research Methods
Xu Jia, Hanghang Zhang, Xiangfu Jiang, Yaling Lu, Wenjie Liu, Jianna Yu
Summary: This study used ambient pressure electrospray ionisation ion mobility spectrometry coupled to HPLC to detect alkaloids from different parts of Sophora alopecuroides L. extracts, revealing the distribution of major alkaloids and providing extra separation ability to resolve co-eluted peaks. The method improved signal-to-noise ratio and maintained high resolving power, demonstrating its potential for qualitative and quantitative analysis of alkaloids.
PHYTOCHEMICAL ANALYSIS
(2021)