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PEG-400 [poly(ethylene glycol-400)] was found to improve the Pd(OAc)2/DABCO-catalyzed aqueous Suzuki-Miyaura and Stille cross-coupling reactions. In the presence of Pd(OAc)2, DABCO, and PEG-400, a variety of aryl halides were coupled with arylboronic acids or organotin compounds efficiently to afford the corresponding cross-coupled products in moderate to excellent yields. The turnover numbers was up to 900,000 for the Suzuki-Miyaura reaction and up to 9800 for the Stille reaction. The catalyst system was also effective for Heck and Sonogashira cross-coupling reactions to some extent. 相似文献
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A metallic glass matrix composite (MGMC) reinforced by copper short fibers has been prepared by warm extrusion of powders, and its deformation behavior at room temperature and in the supercooled liquid region of the metallic glass has been investigated. A mixture of Ni59Zr20Ti16Si2Sn3 metallic glass powders and copper powders is extruded in the supercooled liquid region of the metallic glass with an extrusion ratio of 5. The volume fraction of the copper phase is 0.2. After extrusion, initially spherical powders are elongated along the extrusion direction; no pores are visible. The MGMC shows a high failure strength of around 1.85 GPa, slightly lower than that of the as-cast Ni59Zr20Ti16Si2Sn3 metallic glass, under uniaxial compression. However, due to the crack bridging mechanism produced by the randomly distributed copper short fibers, the MGMC does not catastrophically fail by a single shear band propagating across the whole monolithic sample. In the supercooled liquid region of the metallic glass, the MGMC shows large elongation to failure but fails by cavitation due to the preexisting Ni-based crystalline powders. 相似文献
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M. Abdel-Bary S. Abdel-Samad R. Bilger K.-Th. Brinkmann H. Clement S. Dshemuchadse E. Dorochkevitch H. Dutz W. Eyrich A. Erhardt D. Filges A. Filippi H. Freiesleben M. Fritsch R. Geyer A. Gillitzer D. Hesselbarth B. Jakob L. Karsch K. Kilian H. Koch J. Kreß E. Kuhlmann S. Marcello S. Marwinski S. Mauro W. Meyer P. Michel K. Möller H. P. Morsch L. Naumann N. Paul M. Richter E. Roderburg M. Rogge A. Schamlott M. Schmitz P. Schönmeier M. Schulte-Wissermann W. Schroeder T. Sefzick F. Stinzing G.Y. Sun G.J. Wagner M. Wagner A. Wilms P. Wintz S. Wirth P. Zupranski 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):127-137
The reaction pp → ppη was measured at excess energies of 15 and 41 MeV at an external target of the Jülich Cooler Synchrotron COSY with the time-of-flight
spectrometer. About 25000 events were measured for the excess energy of 15 MeV and about 8000 for 41 MeV. Both protons of
the process ppη were detected with an acceptance of nearly 100% and the η was reconstructed by the missing-mass technique. For both excess
energies the angular distributions are found to be nearly isotropic. In the invariant-mass distributions strong deviations
from the pure phase space distributions are seen.
Received: 24 May 2002 / Accepted: 20 September 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: e.roderburg@fz-juelich.de
Communicated by M. Gar?on 相似文献
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Ya.?A.?Berdnikov V.?T.?Kim V.?F.?Kosmach M.?M.?RyzhinskiyEmail author V.?M.?Samsonov M.?E.?Zavatsky 《The European Physical Journal A - Hadrons and Nuclei》2005,26(2):179-184
Two important initial-state nuclear effects in hadron-nucleus collisions are considered. The ratios of inclusive differential
cross-sections for Drell-Yan dimuon production are calculated. The calculated results are compared to the E866 data. It is
shown that the consideration of multiple soft rescatterings of incident quarks in nuclei and initial-state quark energy loss
effects allow to get a good agreement between the calculated results and the experimental data. 相似文献
47.
流动注射化学发光测定甲基对硫磷 总被引:12,自引:1,他引:11
首次研究了农药甲基对硫磷在碱性介质中(pH:11.5~12.0)与鲁米诺和过氧化氢产生化学发光的行为及反应机理,并发现水溶性高分子聚乙二醇对该反应具有显著的增效作用,据此建立了流动注射化学发光测定甲基对硫磷的新方法。甲基对硫磷的浓度在 5×10-8~1.0 ×10-5g/mL范围内与化学发光强度呈良好的线性关系;检出限为 2×10-8g/mL;对 1.0×10-6g/mL甲基对硫磷进行了11次平行测定,相对标准偏差小于4%;标准加入回收率为83%~94%。该法应用于谷物中农药残余量的测定,结果满意。 相似文献
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2‐Bromobenzaldehydes are condensed and cyclized with arylhydrazines (or their hydrochlorides) in PEG‐400 at 110 °C in the presence of a catalytic amount of a copper(I) salt along with a base to give 1‐aryl‐1H‐indazoles in high yields. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献