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991.
We have studied physical properties and crystal structures for oxygen-deficient phases of the cubic ordered-perovskite cuprate, Sr2Cu(Re0.69Ca0.31)Oy (y=6.0−5.4). It was found that the magnetic state undergoes phase transition from ferrimagnetic long-range order for y?5.9 to paramagnetism for y?5.7 via re-entrant-type spin-glass randomness in the narrow composition range around y∼5.8, as the oxygen content y decreases. The electrical resistivity becomes insulated, and the lattice constant expands simultaneously with decrease in y. The abrupt suppression of the ferrimagnetic state was observed in the oxygen-deficiency phase around 5.9?y?5.7. This is presumably attributed to microscopic phase separation accompanied by the partial cut-off of the Cu–O–Cu antiferromagnetic correlation path, which is caused by cation disorder and reduction of the oxidation state of the cations. 相似文献
992.
We investigated desorption of chlorine atoms on Si (1 1 1)-(7 × 7) surfaces induced by hole injection from scanning tunneling microscope tips. The hole-induced desorption of chlorine atoms had a threshold bias voltage corresponding to the energy position of the S3 surface band originated in Si backbonds. The chlorine atom desorption rate was almost proportional to the square of the tunneling current. We have discussed possible mechanisms that two holes injected into Si surface states get localized at the backbonds of chlorinated Si adatoms, which induces the rupture of Cl-Si bonds to result in chlorine atom desorption. 相似文献
993.
K. Matsuta M. Mihara T. Nagatomo R. Matsumiya S. Momota T. Ohtsubo T. Izumikawa H. Hirano S. Takahashi D. Nishimura J. Komurasaki A. Kitagawa M. Kanazawa M. Torikoshi S. Sato M. Fukuda T. Minamisono T. Sumikama K. Tanaka M. Takechi D. Ishikawa S. A. Pahlovy M. Nagao Y. Nojiri J. R. Alonso G. F. Krebs T. J. M. Symons 《Hyperfine Interactions》2007,174(1-3):65-69
A brief review is presented of recent work with the Precision Penning Trap Mass Spectrometer, formerly at MIT, now at Florida
State University. This includes atomic mass comparisons using single trapped ions; mass comparisons using two simultaneously
trapped ions alternated between large and small cyclotron radii; and measurement of the dipole moment of a molecular ion using
the polarizability-induced shift in cyclotron frequency. 相似文献
994.
Shinya Kanemura Koichi Matsuda Toshihiko Ota Serguey Petcov Tetsuo Shindou Eiichi Takasugi Koji Tsumura 《The European Physical Journal C - Particles and Fields》2007,51(4):927-931
We study how to incorporate CP violation in the Froggatt–Nielsen (FN) mechanism. To this end, we introduce non-renormalizable interactions with a flavor
democratic structure to the fermion mass generation sector. It is found that at least two iso-singlet scalar fields with a
discrete symmetry imposed are necessary to generate CP violation due to the appearance of the relative phase between their vacuum expectation values. In the simplest model, the
ratios of quark masses and the Cabibbo–Kobayashi–Maskawa (CKM) matrix including the CP violating phase are determined by the CKM element |Vus| and the ratio of two vacuum expectation values of FN fields, R=|R|eiα (a magnitude and a phase). It is demonstrated how the angles φi (i=1,...,3) of the unitarity triangle and the CKM off-diagonal elements |Vub| and |Vcb| are predicted as a function of |Vus|, |R| and α. Although the predicted value of the CP violating phase does not agree with the experimental data within the simplest model, the basic idea of our scenario would
be promising if one wants to construct a more realistic model of flavor and CP violation.
PACS 11.30.Er; 12.60.-i 相似文献
995.
Yousuke Tsuneyoshi Shozo Tomonaga Mari Asechi Koji Morishita D Michael Denbow Mitsuhiro Furuse 《BMC neuroscience》2007,8(1):37
Background
Carnosine (β-alanyl-L-histidine) is a putative neurotransmitter and has a possible role in neuron-glia cell interactions. Previously, we reported that carnosine induced hyperactivity in chicks when intracerebroventricularly (i.c.v.) administered. In the present study, we focused on other β-alanyl dipeptides to determine if they have novel functions. 相似文献996.
Akane Agui Masaichiro Mizumaki Koji Matsumoto Junichi Sayama 《Journal of Physics and Chemistry of Solids》2007,68(11):2148-2152
We have carried out X-ray absorption measurements with its magnetic circular dichroism (MCD) of perpendicular magnetic films of DyxCo100−x (15?x?33) at Dy M4,5 and Co L2,3 absorption edges to investigate electronic and spin states of the Dy 4f and Co 3d states, respectively. The replacement of major spin between Dy 4f and Co3d is clearly observed in the spectra between 20?x?25. The expected values of the orbital angular moment ∣〈Lz〉∣ of Dy 4f were estimated to be 1.4-0.8 μB while that of Co 3d was estimated to be around 0.2 μB. 相似文献
997.
Nakao H Hayashi H Iwata F Karasawa H Hirano K Sugiyama S Ohtani T 《Langmuir : the ACS journal of surfaces and colloids》2005,21(17):7945-7950
We report a simple method to functionalize DNA with pi-conjugated polymer, forming highly aligned and integrated arrays of pi-conjugated polymer nanowires of a few nanometers diameter. pi-conjugated polymer, polyphenazasiline, having alkylammonium salts on the N atom (PPhenaz-TMA), synthesized in this study can be directly attached to DNA, which can be organized along stretched and aligned DNA molecules on surfaces as a template. Furthermore, PPhenaz-TMA/DNA nanowires were stretched and aligned on surfaces, even when PPhenaz-TMA/DNA complexes formed in solutions. The resulting PPhenaz-TMA/DNA nanowires could be easily converted to oxidized states or metallic nanowires by using adequate oxidant or metal salts. The direct visualization of PPhenaz-TMA/DNA nanowires and its structural changes have been studied by atomic force microscopy and scanning near-field optical microscopy. 相似文献
998.
Furuta T Sakai M Hayashi H Asakawa T Kataoka F Fujii S Suzuki T Suzuki Y Tanaka K Fishkin N Nakanishi K 《Chemical communications (Cambridge, England)》2005,(36):4575-4577
An artificial phospholipid, possessing saturated alkyl chains as a membrane anchor and protein recognition site as well as an Fe(III)-EDTA moiety as a protein cleavable polar head group, was designed and synthesized based on the amidite method for the purpose of examination of cleavage of integral membrane proteins. 相似文献
999.
We report a new sample target plate for MALDI-TOF mass spectrometry made of SiO2 with 30 nm Pt dots for which a highly reproducible and improved DNA analysis was achieved. 相似文献
1000.