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71.
Christopher J. H. Smalley Harriet E. Hoskyns Colan E. Hughes Duncan N. Johnstone Tom Willhammar Mark T. Young Christopher J. Pickard Andrew J. Logsdail Paul A. Midgley Kenneth D. M. Harris 《Chemical science》2022,13(18):5277
We report the crystal structure of a new polymorph of l-tyrosine (denoted the β polymorph), prepared by crystallization from the gas phase following vacuum sublimation. Structure determination was carried out by combined analysis of three-dimensional electron diffraction (3D-ED) data and powder X-ray diffraction (XRD) data. Specifically, 3D-ED data were required for reliable unit cell determination and space group assignment, with structure solution carried out independently from both 3D-ED data and powder XRD data, using the direct-space strategy for structure solution implemented using a genetic algorithm. Structure refinement was carried out both from powder XRD data, using the Rietveld profile refinement technique, and from 3D-ED data. The final refined structure was validated both by periodic DFT-D calculations, which confirm that the structure corresponds to an energy minimum on the energy landscape, and by the fact that the values of isotropic 13C NMR chemical shifts calculated for the crystal structure using DFT-D methodology are in good agreement with the experimental high-resolution solid-state 13C NMR spectrum. Based on DFT-D calculations using the PBE0-MBD method, the β polymorph is meta-stable with respect to the previously reported crystal structure of l-tyrosine (now denoted the α polymorph). Crystal structure prediction calculations using the AIRSS approach suggest that there are three other plausible crystalline polymorphs of l-tyrosine, with higher energy than the α and β polymorphs.A new polymorph of l-tyrosine is reported, with the crystal structure determined by combined analysis of 3D-ED data and powder XRD data, augmented by information from periodic DFT-D calculations and solid-state 13C NMR data. 相似文献
72.
The work function of hydrothermally synthesized UO2 and the implications for semiconductor device fabrication 下载免费PDF全文
Christopher Young James Petrosky J. Matthew Mann Eric M. Hunt David Turner Tony Kelly 《固体物理学:研究快报》2016,10(9):687-690
The photoelectric work function of nearly stoichiometric (111) and (100) hydrothermally grown UO2 was measured to be 6.28 ± 0.36 eV and 5.80 ± 0.36 eV, respectively. Candidate metals for electrical contacts are identified for both rectifying and non‐rectifying contacts based on work function, lattice compatibility, and electrical conductivity. 相似文献
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Dr. Chi Kyung Kim Taeho Kim In‐Young Choi Min Soh Dr. Dohoung Kim Young‐Ju Kim Dr. Hyunduk Jang Hye‐Sung Yang Dr. Jun Yup Kim Dr. Hong‐Kyun Park Dr. Seung Pyo Park Sangseung Park Dr. Taekyung Yu Prof. Byung‐Woo Yoon Prof. Seung‐Hoon Lee Prof. Taeghwan Hyeon 《Angewandte Chemie (International ed. in English)》2012,51(44):11172-11172
76.
Jin Young Lee Yong Han Lee Yong Gwan Byun 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):641-649
Abstract A new (E)-pyrene-1-carbaldehyde O-tert-butyldimethylsilyl oxime 3 was synthesized for the detection of chemical warfare nerve agents, O-isopropyl methylphosphonofluoridate (GB) and O-pinacolyl methylphosphonofluoridate (GD). 1H NMR spectrum showed that the tert-butyldimethylsilyl (TBDMS) group was deprotected using TBAF and the oximate supernucleophile was made. Upon addition of chemical warfare agents (GB and GD) (50 mol%), the reaction was completely finished within 5 min and also the color change of reaction mixture was observed under a hand-held UV lamp with the naked eye. 相似文献
77.
A photoelectrochemical reactor constructed as a proton exchange membrane fuel cell was utilized to electrochemically enhance the photocatalytic decomposition of gas-phase isopropanol. Nafion membrane was employed to serve as solid electrolyte to establish an electrochemical circuit for the gaseous photocatalytic reaction. The electrical current density of photoanode was found to correspond to the variation of the applied bias and relative humidity of the inlet gas. Photocatalytic decomposition rate was remarkably increased by 20 % by applying a bias potential of 5 V. The effect of relative humidity exhibited multiple effects for membrane conductivity of Nafion and efficiency of photocatalytic decomposition reaction. 相似文献
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Recently, extracts from the pericarp of mangosteen, Garcinia mangostana L., exhibited various pharmacological properties such as anti-oxidative, anti-inflammatory, anti-bacterial and chemopreventive activities. Albeit it has diverse application, there is little information about its pharmacokinetic aspects. Thus, the present study was undertaken to develop the simultaneous determination of α- and γ-mangostins (α- and γ-MG), major and active compounds, from extracts for the application of pharmacokinetic studies in mice using combined liquid chromatography–tandem mass-spectrometry and microsampling systems. The intra- and inter-validation, precision, accuracy, stability, recovery and matrix effects of α- and γ-MG were conducted in mouse plasma. Based on the developed analytical methods, pharmacokinetic parameters of α- and γ-MG after intravenous and oral administration of mangosteen extract were calculated. In sample preparation steps, the biological samples were deproteinized by acetonitrile and chromatographic separation was accomplished on a C18 column. The detection was accomplished by multiple-reaction monitoring scanning after electrospray ionization source in the positive ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 411.062 → 354.900, 397.384 → 340.900, and 808.379 → 527.200 for α- and γ-MG and docetaxel (internal standard), respectively. The total run time was 5 min. The results provided a meaningful basis for the preclinical and clinical application of mangosteen extract. 相似文献
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The racent interest in the conformational and configurational relationships in the carane serises1 prompts us to report an abnrnality observed in the solvelysis of (m%+)-3,4-epoxycarane, xs1, with a sodium acetate buffered solution of glaacial acetic acid.2 相似文献