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991.
Koizumi H Uda S Fujiwara K Nozawa J 《Langmuir : the ACS journal of surfaces and colloids》2011,27(13):8333-8338
The effect of an external ac electric field on the nucleation rate of hen egg white lysozyme crystals increased with an increase in the concentration of the precipitant used, which enabled the design of an electric double layer (EDL) formed at the inner surface of the drop in the oil. This is attributed to the thickness of the EDL controlled by the ionic strength of the precipitant used. Control of the EDL formed at the interface between the two phases is important to establishing this novel technique for the crystallization of proteins under the application of an external ac electric field. 相似文献
992.
Yoshimasa Makita Kenta FuruyoshiKeisuke Ikeda Tomoyuki FujitaShin-ichi Fujiwara Masahiro EharaAkiya Ogawa 《Tetrahedron letters》2011,52(32):4129-4131
A cyclotriveratrylene (CTV)-capped azaphosphatrane 4, which contains an endohedral proton within the cavity of the azaphosphatrane, was synthesized in high yield and then characterized. The endohedral proton of 4 was highly sheltered from strongly basic conditions by the CTV-capped structure. 相似文献
993.
Electron energy distributions upstream of a current-free double layer (CFDL) contained in a low-collisional plasma are modeled and compared with experimental results. The experimentally observed electron energy probability functions (EEPFs) with a depleted tail above the energy corresponding to the potential drop of the CFDL can be well approximated by a Druyvesteyn distribution function. Theoretical effective electron temperatures for the Druyvesteyn distribution are in good agreement with the values obtained from the experimental EEPFs over the range of pressure where the CFDL is observed. 相似文献
994.
Fluorescence spectroscopy of single proteins at liquid-helium temperatures reveals a relation between structural dynamics and biological functions of the proteins. The technical difficulties in detecting visible fluorescence are chromatic aberration and optical background. They were overcome by a new optical design using reflective optics and employing two-photon excitation. The fluorescence spectrum of single green-fluorescent proteins taken at a temperature of 1.5 K makes a distinction between different metastable conformations that last for tens of seconds. 相似文献
995.
Fujiwara MC Amoretti M Amsler C Bonomi G Bouchta A Bowe PD Canali C Carraro C Cesar CL Charlton M Doser M Fontana A Funakoshi R Genova P Hangst JS Hayano RS Jørgensen LV Kellerbauer A Lagomarsino V Landua R Lodi-Rizzini E Macri M Madsen N Manuzio G Mitchard D Montagna P Pruys H Regenfus C Rotondi A Testera G Variola A Venturelli L van der Werf DP Yamazaki Y Zurlo N;ATHENA Collaboration 《Physical review letters》2008,101(5):053401
We demonstrate temporally controlled modulation of cold antihydrogen production by periodic RF heating of a positron plasma during antiproton-positron mixing in a Penning trap. Our observations have established a pulsed source of atomic antimatter, with a rise time of about 1 s, and a pulse length ranging from 3 to 100 s. Time-sensitive antihydrogen detection and positron plasma diagnostics, both capabilities of the ATHENA apparatus, allowed detailed studies of the pulsing behavior, which in turn gave information on the dependence of the antihydrogen production process on the positron temperature T. Our data are consistent with power law scaling T (-1.1+/-0.5) for the production rate in the high temperature regime from approximately 100 meV up to 1.5 eV. This is not in accord with the behavior accepted for conventional three-body recombination. 相似文献
996.
997.
Katoono R Kawai H Fujiwara K Suzuki T 《Chemical communications (Cambridge, England)》2008,(40):4906-4908
The syn-atropisomers of the title bis(tertiary amide)s were designed as six-bladed molecular propellers based on the "directing effects" of amide dipoles; the helicity of the propeller is biased to prefer one handedness upon the attachment of point chirality to the amide nitrogens to attain stronger circular-dichroism activity than for the non-propeller-shaped anti-isomers. 相似文献
998.
Nohara T Okamoto K Matsushita S Fujiwara Y Ikeda T Miyashita H Ono M Yoshimitsu H Kansui H Kunieda T 《Chemical & pharmaceutical bulletin》2008,56(7):1015-1017
Previously, we reported an interesting reaction by which esculeogenin A [(5alpha,22S,23S,25S)-3beta,23,27-trihydroxyspirosolane], a sapogenol of tomato-saponin, esculeoside A, was easily converted into a pregnane derivative, 5alpha-pregn-16-en-3beta-ol-20-one, merely by refluxing with pyridine and water. Its chemical mechanism including air oxidation is here described. 相似文献
999.
Ono M Shiono Y Yanai Y Fujiwara Y Ikeda T Nohara T 《Chemical & pharmaceutical bulletin》2008,56(10):1499-1501
A new steroidal glycoside and a new phenyl glycoside have been isolated from a ripe cherry tomato [Lycopersicon esculentum var. cerasiforme (DUNAL) ALEF., Solanaceae] along with two known steroidal alkaloid glycosides, esculeoisides A and B, and five aromatic compounds, zizibeoside I, benzyl alcohol beta-gentiobioside, rutin, methyl caffeate, and phenylalanine. Their chemical structures were determined on the basis of spectroscopic data as well as chemical evidence. 相似文献
1000.
M. Takeuchi T. Imanishi D. Ushijima K. Kawashima K. Fujiwara 《Physica E: Low-dimensional Systems and Nanostructures》1998,2(1-4)
We have investigated field-induced features of optical transitions in asymmetric double-well superlattices (ADW-SLs) with and without barrier sequence modulation by low-temperature photocurrent (PC) spectroscopy. The difference between the heavy-hole confinement energies in the wide and narrow wells results in two types of Stark-ladder transitions, so that four ±1st-order spatially indirect transitions are expected to exist in the ADW-SL. The oscillator strength of these indirect transitions is affected by the strength and the direction of coupling between the wide and narrow wells. The introduction of the barrier sequence modulation into the ADW-SL realizes the control of these coupling mechanisms. This technique is a new method to modulate the oscillator strength of the indirect Stark-ladder transitions. 相似文献