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101.
As part of a wider study into the use of smartphones as solar ultraviolet radiation monitors, this article characterizes the ultraviolet A (UVA; 320–400 nm) response of a consumer complementary metal oxide semiconductor (CMOS)‐based smartphone image sensor in a controlled laboratory environment. The CMOS image sensor in the camera possesses inherent sensitivity to UVA, and despite the attenuation due to the lens and neutral density and wavelength‐specific bandpass filters, the measured relative UVA irradiances relative to the incident irradiances range from 0.0065% at 380 nm to 0.0051% at 340 nm. In addition, the sensor demonstrates a predictable response to low‐intensity discrete UVA stimuli that can be modelled using the ratio of recorded digital values to the incident UVA irradiance for a given automatic exposure time, and resulting in measurement errors that are typically less than 5%. Our results support the idea that smartphones can be used for scientific monitoring of UVA radiation. 相似文献
102.
Karine A. Eliazyan Aram M. Knyazyan Vergush A. Pivazyan Emma A. Ghazaryan Siranush V. Harutyunyan Aleksandr P. Yengoyan 《Journal of heterocyclic chemistry》2013,50(5):1083-1088
By interaction of N‐methyl(ethyl)‐dithiocarbamate sodium salt with 3‐chloro‐pentane‐2,4‐dion the 1‐(3‐alkyl‐4‐methyl‐2‐thioxo‐2,3‐dihydro‐thiazol‐5‐yl)‐ethanones 1 , 2 and corresponding oximes 7 , 8 were synthesized. On the basis of the mentioned compounds hydrazono ( 3 , 4 ), ureayl and thioureayl ( 5 , 6 ) derivatives, substituted oximes ( 9 , 10 ) and azinyl oximes ( 11 , 12 ) were obtained. The structures of synthesized compounds were confirmed by proton nuclear magnetic resonance spectroscopy and elemental analysis. The pesticidal activities of synthesized compounds were studied. Some of the synthesized compounds simultaneously have shown growth stimulant and fungicidal activity. 相似文献
103.
The asymmetric syntheses of novel dihydroxyhomoprolines have been achieved using the doubly diastereoselective conjugate additions of the antipodes of lithium N-benzyl-N-(α-methylbenzyl)amide to a set of four chiral α,β-unsaturated esters (derived from d-pentoses) as one of the key steps. A full account of the diastereoselectivity observed in these conjugate additions is presented and the stereochemical outcomes of these reactions have been established unambiguously via a combination of hydrogenolytic chemical correlation and single crystal X-ray diffraction analyses. A tandem hydrogenolysis/intramolecular reductive amination reaction was then used to create the corresponding enantiopure pyrrolidines, providing access to (2′S,3′S,4′R)-dihydroxyhomoproline and (2′S,3′R,4′S)-dihydroxyhomoproline after deprotection. 相似文献
104.
van der Waals corrected density functional calculations of the adsorption of benzene on the Cu (111) surface
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We investigate the performance of several van der Waals (vdW) functionals at calculating the interactions between benzene and the copper (111) surface, using the local orbital approach in the SIESTA code. We demonstrate the importance of using surface optimized basis sets to calculate properties of pure surfaces, including surface energies and the work function. We quantify the errors created using (3 × 3) supercells to study adsorbate interactions using much larger supercells, and show non‐negligible errors in the binding energies and separation distances. We examine the eight high‐symmetry orientations of benzene on the Cu (111) surface, reporting the binding energies, separation distance, and change in work function. The optimized vdW‐DF(optB88‐vdW) functional provides superior results to the vdW‐DF(revPBE) and vdW‐DF2(rPW86) functionals, and closely matches the experimental and experimentally deduced values. This work demonstrates that local orbital methods using appropriate basis sets combined with a vdW functional can model adsorption between metal surfaces and organic molecules. 相似文献
105.
106.
Kesler Michael S. McGuire Michael A. Conner Ben Rios Orlando Murphy Bart Carter William Henderson Hunter B. Ludtka Gerard M. Kisner Roger A. 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7449-7457
Journal of Thermal Analysis and Calorimetry - A new thermal analysis technique is described that allows measurements to be performed on bulk samples at extreme heating and cooling rates and in high... 相似文献
107.
Oz E Deng S Katsouleas T Muggli P Barnes CD Blumenfeld I Decker FJ Emma P Hogan MJ Ischebeck R Iverson RH Kirby N Krejcik P O'Connell C Siemann RH Walz D Auerbach D Clayton CE Huang C Johnson DK Joshi C Lu W Marsh KA Mori WB Zhou M 《Physical review letters》2007,98(8):084801
The onset of trapping of electrons born inside a highly relativistic, 3D beam-driven plasma wake is investigated. Trapping occurs in the transition regions of a Li plasma confined by He gas. Li plasma electrons support the wake, and higher ionization potential He atoms are ionized as the beam is focused by Li ions and can be trapped. As the wake amplitude is increased, the onset of trapping is observed. Some electrons gain up to 7.6 GeV in a 30.5 cm plasma. The experimentally inferred trapping threshold is at a wake amplitude of 36 GV/m, in good agreement with an analytical model and PIC simulations. 相似文献
108.
Pfeifer P Aston L Banks M Barker S Burress J Carter S Coleman J Crockett S Faulhaber C Flavin J Gordon M Hardcastle L Kallenborn Z Kemiki M Lapilli C Pobst J Schott R Shah P Spellerberg S Suppes G Taylor D Tekeei A Wexler C Wood M Buckley P Breier T Downing J Eastman S Freeze P Graham S Grinter S Howard A Martinez J Radke D Vassalli T Ilavsky J 《Chaos (Woodbury, N.Y.)》2007,17(4):041108
109.
Large Hexagonal Bi‐ and Trilayer Graphene Single Crystals with Varied Interlayer Rotations
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Zheng Yan Yuanyue Liu Long Ju Zhiwei Peng Dr. Jian Lin Dr. Gunuk Wang Dr. Haiqing Zhou Changsheng Xiang E. L. G. Samuel Carter Kittrell Dr. Vasilii I. Artyukhov Prof. Feng Wang Prof. Boris I. Yakobson Prof. James M. Tour 《Angewandte Chemie (International ed. in English)》2014,53(6):1565-1569
Bi‐ and trilayer graphene have attracted intensive interest due to their rich electronic and optical properties, which are dependent on interlayer rotations. However, the synthesis of high‐quality large‐size bi‐ and trilayer graphene single crystals still remains a challenge. Here, the synthesis of 100 μm pyramid‐like hexagonal bi‐ and trilayer graphene single‐crystal domains on Cu foils using chemical vapor deposition is reported. The as‐produced graphene domains show almost exclusively either 0° or 30° interlayer rotations. Raman spectroscopy, transmission electron microscopy, and Fourier‐transformed infrared spectroscopy were used to demonstrate that bilayer graphene domains with 0° interlayer stacking angles were Bernal stacked. Based on first‐principle calculations, it is proposed that rotations originate from the graphene nucleation at the Cu step, which explains the origin of the interlayer rotations and agrees well with the experimental observations. 相似文献
110.
Organozinc Pivalate Reagents: Segregation,Solubility, Stabilization,and Structural Insights
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Dr. Alberto Hernán‐Gómez Emma Herd Prof. Eva Hevia Dr. Alan R. Kennedy Prof. Dr. Paul Knochel Prof. Dr. Konrad Koszinowski Sophia M. Manolikakes Prof. Robert E. Mulvey Christoph Schnegelsberg 《Angewandte Chemie (International ed. in English)》2014,53(10):2706-2710
The pivalates RZnOPiv?Mg(OPiv)X?n LiCl (OPiv=pivalate; R=aryl; X=Cl, Br, I) stand out amongst salt‐supported organometallic reagents, because apart from their effectiveness in Negishi cross‐coupling reactions, they show more resistance to attack by moist air than conventional organometallic compounds. Herein a combination of synthesis, coupling applications, X‐ray crystallographic studies, NMR (including DOSY) studies, and ESI mass spectrometric studies provide details of these pivalate reagents in their own right. A p‐tolyl case system shows that in [D8]THF solution these reagents exist as separated Me(p‐C6H4)ZnCl and Mg(OPiv)2 species. Air exposure tests and X‐ray crystallographic studies indicate that Mg(OPiv)2 enhances the air stability of aryl zinc species by sequestering H2O contaminants. Coupling reactions of Me(p‐C6H4)ZnX (where X=different salts) with 4‐bromoanisole highlight the importance of the presence of Mg(OPiv)2. Insight into the role of LiCl in these multicomponent mixtures is provided by the molecular structure of [(THF)2Li2(Cl)2(OPiv)2Zn]. 相似文献