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A study was conducted on the optical absorption spectra ranging from 233 to 285 nm, which were taken in a region close to the source of evaporation of Cu, in low-pressure helium gas of 100 Torr. Eight band systems for Cu2 dimers designated as system 1 through 8 were identified. The spectroscopic constants for the band origins were derived as follows: [vtilde] ≈ 42 200 cm?1 for system 1, [vtilde]00 = 41 604.74cm?1 for system [vtilde]00 = 39 606.70cm?1 for system [vtilde]00 = 38 124.32cm?1 for system 4, [vtilde]00 = 38 048.65 cm?1 for system 5, 98, [vtilde]00 = 36 834.22cm?1 for system 6, [vtilde]00 = 36 341.55 cm?1 for system 7 and [vtilde]00 = 36 174.99cm?1 for system 8. For all cases in which vibrational constants of the lower state could be determined, it was found that the transition originated from the ground state of Cu2.  相似文献   
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小试样的几何形状尺寸是影响噪声沸腾状态的一个重要的因素. 对于不同几何尺寸的小试样, 沸腾发生时所产生的气泡的尺寸不同, 因而所产生的压力振动的幅度和特征频率就不同. 采用一个归一化因子将不同几何形状尺寸下的实验数据进行统一, 发现振动的特征频率与几何尺寸因子之间存在对数曲线的关系.  相似文献   
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DEPENDENCY OF PHOTON DENSITY ON PRIMARY PROCESS OF CATTLE RHODOPSIN   总被引:6,自引:0,他引:6  
The primary photochemical reactions of cattle rhodopsin suspended in H2O or D2O were compared between excitation with both a weak and an intense picosecond laser pulse (wavelength, 532 nm; duration, 25 ps) at room temperature. The time-dependent change of absorbance at about 575 nm demonstrated that photohodopsin, a precursor of bathorhodopsin, was produced immediately after the excitation with a weak picosecond laser pulse. It decayed to bathorhodopsin with a time constant of 45 ps which is close to the value reported previously [Shichida et al., (1984) Photobiochem. Photobiophys., 7, 221-228]. No deuterium effect was observed in this process. Excitation with an intense laser pulse induced instantaneous increase of the absorbance at about 575 nm and remained at almost constant level on the picosecond time scale, which was in good agreement with the pioneering work [Busch et al., (1972) Proc. Natl. Acad. Sci., USA, 69, 2802-2806]. No deuterium effect was observed in this photochemical process.  相似文献   
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Cyclodextrins (α-CD, β-CD and 2,6-di-O-dimethyl-β-CD (DM-β-CD)) were found to form inclusion compounds with thiophenes (thiophene (T), bithiophene (2T)) in water and in crystalline states. The structures of α-CD–T, β-CD–2T, and DM-β-CD–2T inclusion complexes were determined by X-ray crystallography. DM-β-CD forms a 1:1 cage type complex with 2T. In contrast, β-CD formed 2:3 (CD:guest) complexes with thiophene and α-CD formed 2:3 complexes, both of the channel type. These inclusion complexes were found to polymerize by FeCl3 in the inclusion compounds in water. The products were formed poly-pseudo-rotaxane between cyclodextrins and poly(thiophene) characterized by IR, 1H-NMR and 13C CP/MAS NMR. The molecular weights of the poly-pseudo-rotaxanes with poly(thiophene) were determined by the MALDI-TOF mass spectra to be 3000–5000. In comparison between poly-pseudo-rotaxane (DM-β-CD–poly(thiophene)), authentic poly(thiophene) and the washed DM-β-CD–poly(thiophene) which was washed with DMF to dethread DM-β-CD, these poly-pseudo-rotaxane was characterized by Raman, UV–vis and fluorescence spectra. The maximum emission band of DM-β-CD–poly(thiophene) shifted to a shorter wavelength. The hypsochromic shift was derived from poly-pseudo-rotaxane with DM-β-CD.  相似文献   
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小试样的几何形状尺寸是影响噪声沸腾状态的一个重要的因素. 对于不同几何尺寸的小试样, 沸腾发生时所产生的气泡的尺寸不同, 因而所产生的压力振动的幅度和特征频率就不同. 采用一个归一化因子将不同几何形状尺寸下的实验数据进行统一, 发现振动的特征频率与几何尺寸因子之间存在对数曲线的关系.  相似文献   
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