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排序方式: 共有713条查询结果,搜索用时 218 毫秒
91.
Maeda Y Miyashita J Hasegawa T Wakahara T Tsuchiya T Feng L Lian Y Akasaka T Kobayashi K Nagase S Kako M Yamamoto K Kadish KM 《Journal of the American Chemical Society》2005,127(7):2143-2146
The chemical reduction and oxidation of M@C82 (M = Y, La, and Ce) afford the corresponding anion and cation, respectively, which show unique and interesting chemical reactivities. It is found that the successful reversible gain or loss of electrons by ionization is useful for controlling the stability and reactivity of M@C82 toward both nucleophiles and electrophiles. 相似文献
92.
Ochiai M Takeuchi Y Katayama T Sueda T Miyamoto K 《Journal of the American Chemical Society》2005,127(35):12244-12245
Reported here for the first time is the iodobenzene-catalyzed alpha-oxidation of ketones, in which diacyloxy(phenyl)-lambda3-iodanes generated in situ act as real oxidants of ketones and m-chloroperbenzoic acid serves as a terminal oxidant. Oxidation of a ketone with m-chloroperbenzoic acid in acetic acid in the presence of a catalytic amount of iodobenzene, BF3.Et2O, and water at room temperature under argon affords an alpha-acetoxy ketone in good yield. p-Methyl- and p-chloroiodobenzene also serve as efficient catalysts in this direct oxidation. We found that when the reaction was carried out in the absence of a catalytic amount of iodobenzene, Baeyer-Villiger oxidation of a ketone took place. It is noted that use of water and BF3.Et2O is crucial to the success of this alpha-acetoxylation. 相似文献
93.
The method of measuring f(I) values is proposed as a measure of the adsorption capacity of adsorbents. The f(I) value, a characteristic figure for a particular system, can be obtained chromatogiaphically by measuring the progression rate of zone and the degree of packing of the column. For a system involving a unit concentration of trasns-p-methoxyazobenzene in benzene as standard solution and alumina as adsorbent, optimum conditions for the measurement of f(I) were established. The effects of day-light, pretreatment of column, temperature, flow rate of solution, amount of adsorbent and degree and mode of packing were studied Under optimum conditions, the value of f(I) was reproducible within ±2%. 相似文献
94.
The structure of the 1,3,4,6-tetrakis(isopropylthio)thieno[3,4-c]thiophene dication ( 2 ) prepared from 1,3,4,6-tetrakis(isopropylthio)thieno[3,4-c]thiophene ( 1 ) by two-electron oxidation was investigated by X-ray crystallographic analysis. The results revealed that the positive charges are largely delocalized on the two i-PrS-C-C-C-SPr-i moieties. 相似文献
95.
Kazunori Kurosawa Masahiko Suenaga Takahiko Inazu Tamotsu Yoshino 《Tetrahedron letters》1982,23(50):5335-5338
The title compounds, I, were synthesized by the dialkylation of TosMIC, II, with appropriate bis (halomethyl) compounds, III, under phase-transfer condition, followed by acid hydrolysis. 相似文献
96.
Host 1 based on the phenolphthalein skeleton and two crown ether moieties demonstrated opposite behaviors toward sodium and potassium cations caused by bidirectional complexation. [reaction: see text] 相似文献
97.
98.
Yasuyo Maezawa Yoichiroh Hosokawa Kazunori Okano Mie Matsubara Hiroshi Masuhara 《Applied Physics A: Materials Science & Processing》2010,101(1):127-131
When a stress wave generated by focusing a femtosecond laser is loaded on an animal cell adhered on a substrate, the cell
is detached from the substrate. There are two possible mechanisms for the cell detachment: (a) The cell is detached from a
scaffold coated on a glass plate, and (b) the cell is detached from the glass plate with the scaffold. In this work, we have
studied the cell-detachment mechanism by visualizing the scaffold with a fluorescence probe of quantum dots. When the cell
was detached from the substrate, fluorescence from the scaffold simultaneously disappeared from the glass plate, although
the scaffold was not irradiated by the laser. This indicates that detachment due to the stress wave is attributed to mechanism (a).
On the other hand, when the cell was detached from the substrate by a trypsin treatment, the fluorescence from the scaffold
remained, suggesting mechanism (b). By comparing both results, it is considered that physiological damage of the cell membrane
during the detachment process by femtosecond laser-induced stress wave is less than that due to the trypsin treatment. 相似文献
99.
In this article, we study the diagonal F-threshold, that is, the F-threshold of the maximal ideal with respect to the maximal ideal itself. In particular, we give a formula of the diagonal F-thresholds for binomial hypersurfaces, and compare the diagonal F-thresholds with F-pure thresholds for strongly F-regular binomial hypersurfaces. As a result, we prove that those diagonal F-thresholds always exist and they are rational numbers in that case. 相似文献
100.
We present an analytic study of the physics of the glasma which is a strong classical gluon field created at early stage of high-energy heavy-ion collisions. Our analysis is based on the picture that the glasma just after the collision is made of color electric and magnetic flux tubes extending in the longitudinal direction with their diameters of the order of 1/Qs (Qs is the saturation scale of the colliding nuclei). We find that both the electric and magnetic flux tubes expand outwards and the field strength inside the flux tube decays rapidly in time. Next we investigate whether there exist instabilities against small rapidity-dependent perturbations for a fixed color configuration. We find that the magnetic background field exhibits an instability induced by the fluctuations in the lowest Landau level, and it grows exponentially in the time scale of 1/Qs. For the electric background field we find no apparent instability while the possible relation to the Schwinger mechanism for particle pair creations is suggested. 相似文献