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611.
Within the framework of boundary diffraction wave theory it has been shown that the first bright fringe on either side of
the central dark fringe of the phase knife-edge Fresnel diffraction pattern could be broadened to cover the whole field of
view. Broadening of the first diffraction fringe, instead of conventionally modifying the spatial frequency spectrum, enhances
the sensitivity of the Schlieren system. The use of phase knife-edge as viewing diaphragm in Schlieren diffraction interferometry
not only enhances the fringe contrast but also avoids the loss in phase information as it lets through light from all parts
of the test object and its thin interfacing makes the method suitable even for studying weak disturbances.
相似文献
612.
Small angle neutron scattering studies (SANS) were carried out to understand the formation of third phase in DHDECMP-dodecane-UO2(NO3)2/HNO3 system. It was observed that third phase formation takes place due to the formation of UO2(NO3)2.DHDECMP reverse micelles in the dodecane phase. SANS data obtained were interpreted with particle interaction model using
Baxter sticky spheres model.
相似文献
613.
Abelev BI Aggarwal MM Ahammed Z Anderson BD Arkhipkin D Averichev GS Bai Y Balewski J Barannikova O Barnby LS Baudot J Baumgart S Belaga VV Bellingeri-Laurikainen A Bellwied R Benedosso F Betts RR Bhardwaj S Bhasin A Bhati AK Bichsel H Bielcik J Bielcikova J Bland LC Blyth SL Bombara M Bonner BE Botje M Bouchet J Brandin AV Burton TP Bystersky M Cai XZ Caines H Calderón de la Barca Sánchez M Callner J Catu O Cebra D Cervantes MC Chajecki Z Chaloupka P Chattopadhyay S Chen HF Chen JH Chen JY 《Physical review letters》2008,100(23):232003
We report a new STAR measurement of the longitudinal double-spin asymmetry A(LL) for inclusive jet production at midrapidity in polarized p + p collisions at a center-of-mass energy of sqrt[s]=200 GeV. The data, which cover jet transverse momenta 5
相似文献
614.
Aggarwal MM Ahammed Z Angelis AL Antonenko V Arefiev V Astakhov V Avdeitchikov V Awes TC Baba PV Badyal SK Bathe S Batiounia B Baumann C Bernier T Bhalla KB Bhatia VS Blume C Bucher D Büsching H Carlén L Chattopadhyay S Decowski MP Delagrange H Donni P Majumdar MR El Chenawi K Dubey AK Enosawa K Fokin S Frolov V Ganti MS Garpman S Gavrishchuk O Geurts FJ Ghosh TK Glasow R Guskov B Gustafsson HA Gutbrod HH Hrivnacova I Ippolitov M Kalechofsky H Kamermans R Karadjev K Karpio K Kolb BW Kosarev I 《Physical review letters》2008,100(24):242301
Neutral pion transverse momentum spectra were measured in p+C and p+Pb collisions at sqrt[S{NN}]=17.4 GeV at midrapidity (2.3 less than or approximately equal eta{lab} less than or approximately equal 3.0) over the range 0.7 less than or approximately equal p{T} less than or approximately equal 3.5 GeV/c. The spectra are compared to pi{0} spectra measured in Pb+Pb collisions at sqrt[S{NN}]=17.3 GeV in the same experiment. For a wide range of Pb+Pb centralities (N{part} less than or approximately equal 300), the yield of pi{0}'s with p{T} greater than or approximately equal 2 GeV/c is larger than or consistent with the p+C or p+Pb yields scaled with the number of nucleon-nucleon collisions (N{coll}), while for central Pb+Pb collisions with N{part}greater than or approximately equal 350, the pi{0} yield is suppressed. 相似文献
615.
Valerio Fasano Nils Winter Adam Noble Varinder K. Aggarwal 《Angewandte Chemie (International ed. in English)》2020,59(22):8502-8506
There is considerable interest in incorporating fluorine into agrochemicals and pharmaceuticals to improve their biological properties. Whilst a number of methods have been reported for installing CH2F and CHF2 groups, they are mainly limited to radical reactions, which are invariably racemic. Herein, we report the divergent, stereospecific reaction of fluoroiodomethyllithium with boronic esters to give α‐fluoro‐boronic esters. These unique intermediates can be readily transformed into the corresponding mono‐ or difluoromethylated compounds through proto‐ or fluorodeboronation, respectively. The use of the highly unstable fluoroiodomethyllithium was key to allowing rapid 1,2‐migration over competing decomposition of the carbanion. DFT calculations informed and supported the experimental findings. 相似文献
616.
Dr. Meganathan Nandakumar Dr. Belén Rubial Dr. Adam Noble Dr. Eddie L. Myers Prof. Dr. Varinder K. Aggarwal 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(3):1203-1207
Stereogenic trifluoromethyl-substituted carbon centers are highly sought-after moieties in pharmaceutical and agrochemical discovery. Here, we show that lithiation–borylation reactions of 2-trifluoromethyl oxirane give densely functionalized and highly versatile trifluoromethyl-substituted α-tertiary boronic esters. The intermediate boronate complexes undergo the desired 1,2-rearrangement of the carbon-based group with complete retentive stereospecificity, a process that was only observed in non-polar solvents in the presence of TESOTf. Although the trifluoromethyl group adversely affects subsequent transformations of the α-boryl group, Zweifel olefinations provide trifluoromethyl-bearing quaternary stereocenters substituted with alkenes, alkynes and ketones. 相似文献
617.
N. L. Misra M. K. Tiwari Bal Govind Vats S. Sanjay Kumar Ajit Kumar Singh G. S. Lodha S. K. Deb P. D. Gupta S. K. Aggarwal 《X射线光谱测定》2014,43(3):152-156
A μ‐XRF study to assess the distribution of uranium and thorium in (U,Th)O2 pellets covering the composition of advanced heavy water reactor (AHWR) fuel pellets prepared by powder metallurgical compaction (PMC) and coated agglomerate pelletization (CAP) routes was made using micro‐focus beam line (BL‐16) of Indus‐2 synchrotron radiation facility. The methodology thus developed was successfully applied to these pellets. The study reveals that the uranium distribution in pellets prepared by PMC route is uniform, whereas the pellets prepared through CAP route have a wide range of compositional variation. In addition, the uniformity in CAP route‐prepared pellets improves with increase in the relative amount of uranium in the pellets. The sample preparation in present methodology is very simple compared with scanning electron microscopy. The study reveals the utility of synchrotron‐based μ‐XRF for fuel pellet characterization of AHWR reactors. Alhough CAP route of fuel pellet preparation requires less exposure of personnel to high radiation dose, the non‐uniformity in the fuel pellet must be considered when using these pellets in reactors. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
618.
N. L. Misra S. Sanjay Kumar Sangita Dhara Ajit Kumar Singh G. S. Lodha Suresh Kumar Aggarwal 《X射线光谱测定》2011,40(5):379-384
Studies on the matrix effects of uranium and thorium on the determinations of each other in their mixed oxides using energy dispersive X‐ray fluorescence (EDXRF) spectrometry with tube and radioisotope excitations of U Lα and Th Lα are reported. An internal standard method for the determination of uranium and thorium in these mixed oxides is found suitable. Comparison of the analytical results of EDXRF determinations of uranium and thorium using tube and radioisotope excitation sources has been made. The analytical methodology involves preparation of mixed oxide calibration/sample mixtures of uranium and thorium oxides, mixing of internal standard yttrium in these mixtures, pelletizing the mixtures after thorough mixing and grinding using boric acid binder and measuring EDXRF spectra of the specimens thus prepared using Rh X‐ray tube as well as 109Cd radioisotope source. The samples were analyzed for uranium and thorium on the basis of the calibration plots obtained by plotting the intensity ratios of the analyte and internal standard characteristic X‐ray lines and their corresponding amount ratios. An average precision of 1.2% (1 s RSD) was observed for the determination of U and Th and the results deviated from the corresponding expected values by 3% on average. Due to the refractory nature of thorium oxide, comparatively more grinding time was required for thorium determinations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
619.
Hudson DD Dekker SA Mägi EC Judge AC Jackson SD Li E Sanghera JS Shaw LB Aggarwal ID Eggleton BJ 《Optics letters》2011,36(7):1122-1124
An octave spanning spectrum is generated in an As?S? taper via 77 pJ pulses from an ultrafast fiber laser. Using a previously developed tapering method, we construct a 1.3 μm taper that has a zero-dispersion wavelength around 1.4 μm. The low two-photon absorption of sulfide-based chalcogenide fiber allows for higher input powers than previous efforts in selenium-based chalcogenide tapered fibers. This higher power handling capability combined with input pulse chirp compensation allows an octave spanning spectrum to be generated directly from the taper using the unamplified laser output. 相似文献
620.
Aggarwal VK Binanzer M de Ceglie MC Gallanti M Glasspoole BW Kendrick SJ Sonawane RP Vázquez-Romero A Webster MP 《Organic letters》2011,13(6):1490-1493
Tertiary allyl- or crotylsilanes have been prepared in high er and dr via the lithiation-borylation reaction of alkyl carbamates with silaboronates. Using a related strategy, quaternary allylsilanes could be accessed in similarly high er. 相似文献