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991.
[reaction: see text] A novel C3V-symmetric scaffold, trindane 7, has been efficiently synthesized from 1,3,5-tris(bromomethyl)-2,4,6-tris(chloromethyl)benzene (1) in six steps with 47% overall yield. The control of all-syn stereochemistry in the tribenzylation step has been achieved by blocking one side of the trindane ring as metal carbonyl complexes. The potential utility of trindane 7 as a receptor skeleton has been examined with a urea derivative 12 toward several anionic guests. 相似文献
992.
Ohne Zusammenfassung 相似文献
993.
Let be a monic irreducible polynomial. In this paper we generalize the determinant formula for of Bae and Kang and the formula for of Jung and Ahn to any subfields of the cyclotomic function field By using these formulas, we calculate the class numbers of all subfields of when and are small.
994.
Nakano T Ahn DS Ahn JK Akimune H Asano Y Chang WC Daté S Ejiri H Fujimura H Fujiwara M Hicks K Hotta T Imai K Ishikawa T Iwata T Kawai H Kim ZY Kino K Kohri H Kumagai N Makino S Matsumura T Matsuoka N Mibe T Miwa K Miyabe M Miyachi Y Morita M Muramatsu N Niiyama M Nomachi M Ohashi Y Ooba T Ohkuma H Oshuev DS Rangacharyulu C Sakaguchi A Sasaki T Shagin PM Shiino Y Shimizu H Sugaya Y Sumihama M Toyokawa H Wakai A Wang CW Wang SC Yonehara K Yorita T Yoshimura M Yosoi M Zegers RG 《Physical review letters》2003,91(1):012002
The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed at 1.54+/-0.01 GeV/c(2) with a width smaller than 25 MeV/c(2) and a Gaussian significance of 4.6sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state (uuddsmacr;) that decays into a K+ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model. 相似文献
995.
996.
997.
S.-Y. Lee T.-H. Kim D.-I. Suh J.-E. Park J.-H. Kim C.-J. Youn B.-K. Ahn S.-K. Lee 《Physica E: Low-dimensional Systems and Nanostructures》2007,36(2):194-198
This is a report on the electrical characterization of gallium nitride (GaN) nanowire (NW) p–n junction diodes. These diodes were formed by assembling n-GaN NWs on p-Si (1 0 0) substrates using alternating current (AC) dielectrophoresis (DEP). The AC DEP was optimized with a bias voltage of 15 Vp−p at a frequency of 1 kHz. The hetero-junction single GaN nanowire p-n diode (n-GaN NW/p-Si) showed well-defined current rectifying behavior with a forward voltage drop of 1.2–2.0 V at a current density of 10–60 A/cm2. The GaN nanowire p–n diodes had a high parasite resistance in the range of >470 kΩ. We observed that these high resistances were mostly the result of the metal contacts to the n-GaN NWs. We also found that these parasite resistances were reduced by the formation of an additional capping layer on the top of the n-GaN NW as well as high temperature annealing. 相似文献
998.
A. D. Panov J. H. Adams Jr. H. S. Ahn K. E. Batkov G. L. Bashindzhagyan John W. Watts J. P. Wefel J. Wu O. Ganel T. G. Guzik R. M. Gunashingha V. I. Zatsepin J. Isbert K. C. Kim M. Christl E. N. Kouznetsov M. I. Panasyuk E. S. Seo N. V. Sokolskaya J. Chang W. K. H. Schmidt A. R. Fazely 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(4):494-497
This paper reports on the results of measurements performed in the course of the ATIC-2 balloon experiment (2002–2003) for the energy spectra of particles (such as protons; He, C, O, Ne, Mg, Si, and Fe nuclei; and some groups of nuclei) and the all-particle energy spectrum in primary cosmic rays at energies ranging from 50 GeV to 200 TeV. The conclusion is drawn that the energy spectra of protons and helium nuclei differ substantially (the spectrum of protons is steeper) and that the shape of the energy spectra of protons and heavy nuclei cannot be described by a power function. 相似文献
999.
The αη protocol given by Barbosa et al. [G.A. Barbosa, E. Corndorf, P. Kumar, H.P. Yuen, Phys. Rev. Lett. 90 (2003) 227901, quant-ph/0212018] claims to be a secure way of encrypting messages using mesoscopic coherent states. We show that transmission under αη exposes information about the secret key to an eavesdropper, and we estimate the rate at which an eavesdropper can learn about the key. We also consider the consequences of using further randomization to protect the key and how our analysis applies to this case. We conclude that αη is not informationally secure. 相似文献
1000.
Starting from the Bethe Ansatz solution of the open integrable spin-1 XXZ quantum spin chain with diagonal boundary terms, we derive a set of nonlinear integral equations (NLIEs), which we propose to describe the boundary supersymmetric sine-Gordon model BSSG+ with Dirichlet boundary conditions on a finite interval. We compute the corresponding boundary S matrix, and find that it coincides with the one proposed by Bajnok, Palla and Takács for the Dirichlet BSSG+ model. We derive a relation between the (UV) parameters in the boundary conditions and the (IR) parameters in the boundary S matrix. By computing the boundary vacuum energy, we determine a previously unknown parameter in the scattering theory. We solve the NLIEs numerically for intermediate values of the interval length, and find agreement with our analytical result for the effective central charge in the UV limit and with boundary conformal perturbation theory. 相似文献