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711.
A. G. Demekhov V. Yu. Trakhtengerts Y. Hobara M. Hayakawa 《Radiophysics and Quantum Electronics》1999,42(8):625-638
Recent analytical and numerical results concerning the role of the second-order cyclotron resonance effects in formation of
discrete emissions in the magnetosphere are reviewed. Peculiarities of whistler cyclotron interactions with energetic particles
having sharp (step-like or beam-like) distribution functions evolving in space and time are studied. Formation of such distributions
is considered, and an analytical self-consistent theory of the second-order cyclotron resonance effects is developed. In particular,
characteristics of electron beams produced by the interaction of a VLF wave packet from a ground-based transmitter are studied.
It is shown that spatial and temporal gradients of the parallel velocity of the beams formed can be opposite to the case of
a pure adiabatic motion of a single particle. Such a behavior can be significant for the generation of secondary emissions.
It is proven that the optimal conditions for the instability occur for a nonstationary quasi-monochromatic wavelets whose
frequency changes in time. The theory developed permits one to estimate the wave amplification and spatio-temporal characteristics
of these wavelets. Numerical results on beam formation and generation of secondary emissions are presented.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 8, pp. 713–727, August 1999. 相似文献
712.
Eusebio Juaristi Marcos Hernndez‐Rodríguez Heraclio Lpez‐Ruiz Judit Avia Omar Muoz‐Muiz Michiya Hayakawa Dieter Seebach 《Helvetica chimica acta》2002,85(7):1999-2008
The preparation of three new chiral derivatives of DMPU (N,N′‐dimethylpropyleneurea) is described (Schemes 2–4); one type of derivative carries 1‐phenylethyl or 1‐cyclohexylethyl groups at the N‐atoms of the tetrahydropyrimidin‐2(1H)‐one ring ( 2 and 4 ), another type of derivative is substituted at C(4) and C(6) of the heterocyclic ring ( 7 ). The potential of these chiral Lewis bases as promoters in the regio‐ and/or enantioselective addition of 2‐(1,3‐dithianyl)lithium to cyclohex‐2‐en‐1‐one was explored; they are all unable to effect enantioselective addition; the derivatives with branched substituents at the N‐atoms do not shift the addition mode from 1,2 to 1,4, while the 3,4,5,6‐tetrahydro‐1,3,4,6‐tetramethylpyrimidin‐2(1H)‐one does (Scheme 5). The results provide useful information regarding the nature of the nucleophilic organolithium reagent: obviously, the steric hindrance to Li complexation on the CO O‐atom of the tetrahydropyrimidin‐2(1H)‐one by branched substituents at N‐atoms (cf. X‐ray crystal structure of 2 in the Fig.) prevents solvent‐separated‐ion‐pair (SSIP) formation; this was confirmed by PM3 and B3LYP/3‐21‐G(d)//PM3 calculations (Scheme 6). 相似文献
713.
714.
Michiya Hayakawa Makoto Mitani Tohru Yamada Teruaki Mukaiyama 《Macromolecular rapid communications》1996,17(12):865-870
Living ring-opening polymerization of the cyclic carbonate 1,3-dioxepan-2-one was achieved by using the cationic zirconocene complex [Cp2ZrMe]+[B(C6F5)4]− as catalyst at room temperature. A linear relation between conversion and molecular weight of the obtained polymer was observed. Furthermore, block copolymerization of the cyclic carbonate and ε-caprolactone was successfully performed. 相似文献
715.
716.
717.
Kazuhiko Okitsu Yasuhiro Hayakawa Tomuo Yamaguchi Masashi Kumagawa Akira Hirata Syogo Fujiwara Yasunori Okano Nobuyuki Imaishi Shinichi Yoda Toshihiko Oida 《Crystal Research and Technology》1996,31(8):969-978
A mixing experiment of multicomponents melts was performed using a uniform temperature furnace in the Second International Microgravity Laboratories (IML-2) mission. Growth morphologies and Ga concentration profiles were analyzed for the samples with the compositional ratio of 0.5 In–0.5 Ga–1.0 Sb grown under microgravity and on earth. The sample with free surface grown under microgravity was nearly spherical in shape, except some parts with projections. Ga was dispersed homogeneously in the bulk because the mixing was enhanced by Marangoni convection due to the concentration gradient. On the other hand, the sample grown on earth was a double cylindrical shape with different diameters, and Ga concentration decreased from top to bottom, showing clearly the effect of gravity. Many needle crystals were formed in both space and earth samples due to rapid cooling. The average size of the needle crystals grown in space was larger than that of the earth sample. 相似文献
718.
A basic survey on some aspects of four‐dimensional black holes (BHs) is given in these lectures. It covers thermodynamical properties as well as the Attractor Mechanism for extremal BHs in an environment of scalar field background. Some relevant formulæ for the critical points of the BH “effective potential” are discussed, and the simplest example uncovering the attractor behavior, the Maxwell‐Einstein‐dilaton supergravity, is analyzed in detail. Observations on similarities between BH entropy (as given by the Bekenstein‐Hawking entropy‐area formula) and multipartite entanglement of qubits in quantum information theory are reported, as well. Finally, among the latest developments, the moduli space of attractor points for 𝒩 ≥ 2 supergravities is also considered. Based on lectures given by S. Ferrara at the International School of Subnuclear Physics, 45th Course: Search for the “Totally Unexpected” in the LHC era, Erice, Italy, 29 August – 7 September 2007 (Directors: G. 't Hooft – A. Zichichi), and at the III Avogadro Meeting on Theoretical Physics, Alessandria, Italy, 19 – 21 December 2007. 相似文献
719.
Yasuhiro Hayakawa Masahiko Ando Tadanobu Koyama Masashi Kumagawa Tetsuo Ozawa Miyuki Masaki Katsumi Takahashi 《Crystal Research and Technology》1996,31(5):567-575
InxGa1-xAs (x = 0.045) ternary bulk crystals were grown on GaAs seeds from an In–Ga–As solution by the temperature-difference method modified to rotate a growth ampoule. The effect of ampoule rotation on the profiles of the composition and the growth rate were investigated. The In compositional profiles were uniform irrespective of the ampoule rotation. On the other hand, the growth rate at the center of the crystal increased from 40 μm/h at 0 rpm to 55 μm/h at 100 rpm. The profile of growth rate changed from concave to convex toward the seed due to the ampoule rotation. Flow patterns and compositional profiles in the solution were simulated by solving four equations: Navier-Stokes, continuity, energy, and solute diffusion. The ampoule rotation enhanced the transportation of As component from the GaAs feed toward the seed at the central region in the solution. This led to the increase of the growth rate. 相似文献
720.
Kazuya Haraguchi Shinobu Sato Manabu Habu Naomi Yada Mana Hayakawa Masaaki Sasaguri Izumi Yoshioka Kazuhiro Tominaga Shigeori Takenaka 《Electroanalysis》2023,35(8):e202200564
In order to improve the survival rate of oral squamous cell carcinoma (OSCC) patients, a reliable diagnostic method for early OSCC detection is required that is minimally invasive, less burdensome to the patient, and has high sensitivity and specificity. Therefore, we performed the detection of abnormal methylation at three locations in the hTERT promoter region of oral exfoliated cells by employing the ferrocenylnaphthalene diimide (FND)-based electrochemical hybridization assay (FND-EHA) using three types of DNA probe-immobilized electrodes. We also performed liquid cytology using oral exfoliated cells and compared these obtained data to evaluate whether FND- EHA can be used as an OSCC screening system. The results showed a good correlation between this method and conventional OSCC screening, and cytology. In addition, FND-EHA was also able to determine samples that had been ambiguously determined by liquid cytology. This indicates that FND-EHA may be useful as an OSCC screening system. 相似文献