Site-specific phonon density of states discerned using electronic states

We have performed the measurement of the site-specific phonon densities of states (PDOS) discerned using electronic states. As far as we know, no general method could give the site-specific PDOS, although oscillating properties of the individual atoms in nonequivalent positions are not necessarily equivalent. However, the combination of the energy and time domain measurements of the nuclear resonant scattering of synchrotron radiation allows the identification of site-specific PDOS. We measured the site-specific PDOS of iron atoms in magnetite, which is a mixed valent compound, and the difference between partial phonon densities of the iron sites was clearly observed.     

Bunch compression at the SPring-8 linac and successive generation of THz pulse train in the isochronous ring

We have demonstrated the idea of circulating a short, intense linac bunch for some tens of turns in an isochronous ring. We compressed a bunch from the SPring-8 linac to a few picoseconds rms by means of an energy compression system and a beam transport line from the linac to NewSUBARU. The NewSUBARU storage ring was set to a quasi-isochronous condition and the bunch circulated for about 50 turns after injection while maintaining the short bunch length. At the same time, a pulse train of strong coherent synchrotron oscillation from the short bunch was observed.     

Energy spectrum of cosmic-ray muons

Summary The energy spectrum of cosmic-ray muons at sea-level is calculated by the numerical integration of a diffusion equation by assuming a scaling model. The calculated spectrum is in good agreement with the observed data of muons with the zenith angles of 0° and nearly 90°. Furthermore, by this comparison, it is concluded that the scaling model is valid up to the muon energy of 6.9 TeV. It is also found that the survival probability of muons at large zenith angles is in favour of that calculated by Ramana Murthy rather than that obtained by Dau, Carstensen and Jokisch. Two production spectra of muons obtained by Thompson and Whalley and Dauet al. are analysed in reference to the recent experimental data. As a result, it is concluded that the power law exponent of the differential-energy spectrum of muon parent particles is 2.75±0.15 in the muon energy range from 100 GeV to 6.9 TeV.

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Riassunto Si calcola lo spettro di energia dei muoni dei raggi cosmici per mezzo dell'integrazione numerica di un'equazione di diffusione assumendo un modello a scala variabile. Lo spettro calcolato è in buon accordo con i dati osservati dei muoni con angoli di zenith di 0° e quasi 90°. Inoltre da questo confronto si conclude che il modello a scala variabile è valido fino ad energie muoniche di 6.9 TeV. Si trova anche che la probabilità di sopravvivenza dei muoni ad angoli di zenith grandi è in favore di quella calcolata da Ramana Murthy piuttosto che di quella ottenuta da Dau, Cartensen e Jokisch. Si analizzano due spettri di produzione dei muoni ottenuti da Thomson e Whalley e Dauet al. rispetto a recenti dati sperimentali. Come risultato si conclude che l'esponente della legge di potenza dello spettro di energia differenziale delle particelle genitrici dei muoni è 2.75±0.15 nell'intervallo di energia muonica compreso tra 110 GeV e 6.9 TeV.

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Резюме Вычисляется энергетический спектр мюонов космических лучей на уровне моря, использия численное интегрирование уравнения диффузии и предполагая модель подобия. Вычисленный спектр хорошо согласуется с наблюденными данными для мюонов с зенитными углами вблизи 0° и 90°. Из этого сравнения делается вывод, что модель подобия справедлива для энергии мюонов вплоть до 6.9 ТэВ. Отмечается, что вероятность выживания мюонов при больших зенитных углах отдает предпочтение вычислениям Рамана Мурти, а не Дау, Карстенсена и Джокиша. Два спектра образования мюонов, полученные Томпсоном и Валлеем и Дау и др., сравниваются с недавними экспериментальными данными. Из сравнения получено, что показатель степенного закона в дифференциальном энергетическом спектре равен 2.75±0.15 в области энергий мюонов от 110 ГэВ до 6.9 ТэВ.

     

Novel water overlayer growth on Pd(111) characterized with scanning tunneling microscopy and density functional theory

Scanning tunneling microscopy (STM) images of water submonolayers on Pd(111) reveal quasiperiodic and isolated adclusters with internal structure that would ordinarily be ascribed to icelike puckered hexagonal units. However, density functional theory and STM simulations contradict this conventional picture, showing instead that the water adlayers are composed mainly of flat-lying molecules arranged in planar water hexagons. A new rule for two dimensional (2D) water growth is offered that generates the structures observed experimentally from planar hexamer units.     

High sensitivity search for nu;e's from the sun and other sources at KamLAND

Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for nu;(e)'s in the energy range 8.3相似文献   

Charge transport properties for carbazolyl groups pendant poly(glutamate)

Carbazolyl groups pendant poly(glutamate) (PCLG) was prepared to analyze its charge‐transport properties by employing mobility measurements and thermally‐stimulated current (TSC) measurements. The mobility induced TSC (MITSC) model proposed by I.Chen was employed to evaluate the experimental TSC spectra with mobility results. Simulated MITSC spectra showed good agreement in its peak temperature with experimental TSC spectra for PCLG. This suggests that the carrier transport followed the trap‐limited mechanism estimated by the mobility results. Further, the peaks in experimental TSC spectra appeared over the same temperature range as that in thermally‐stimulated polarization current (TSPC) spectra. Since the TSPC spectra were found to be correlated with the dielectric tan δ spectra for PCLG, the peaks in TSPC spectra are attributed to the side‐chain relaxation for PCLG. Therefore, the similarity between TSPC and TSC spectra indicates that the charge‐transport mechanism for PCLG was considerably affected by side‐chain relaxation for PCLG, which would vary the energy state of trap sites and effectively reduces the energy for the release of the carriers trapped on the illuminated surface. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 61–69, 1999     

Allylic-type diindium reagents. Reactivity toward electrophiles and cascade coupling reactions with imines

The allylic-type diindium reagents A and B were prepared from 3-bromo-1-iodopropene (1a) and 4-bromo-2-iodobut-2-ene (1b), respectively, and their reactions with electrophiles were investigated. The diindium reagents A and B were initially reacted with imines and the resulting vinylindium compounds were then treated with organic halides in the presence of Pd(PPh(3))(4) to give linear N-aryl and N-tosyl homoallylic amines. Diindium A is stable in a small amount of water in solvent, whereas B is easily protonated to give a crotylindium reagent. The reaction of B with benzaldehyde gives mainly the 1,3- and 1,5-diols via a spontaneous coupling with two molecules of the aldehyde, in contrast to A, which reacts with one molecule of carbonyl compounds to give the vinylindium compounds.