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61.
We first propose a simple method to deal with the electron-phonon interaction for all states involved in optical transitions and then use the results obtained to derive the equations of the oscillator strengths ? and ?-sum for a defect center including the phonon effects adequately. The derived results are applied to the F center in KCl and discussed in relation to those excluding the dynamical phonon effect. 相似文献
62.
Dye-sensitized photooxygenation of enol ethers of methyl phenylpyruvates () produced diendoperoxides in aprotic solvents, whereas in methanol hydroxylated product was obtained. The reaction scheme is discussed in comparison uith that for the enzymic transformation. 相似文献
63.
64.
A simple Raman probe was realized using a single flexible hollow waveguide (HW). A HW coated with a silver film, which had reasonable transmission and little optical background noise, was used as a bidirectional transmission fiber for both the excitation and collection of Raman scattered light. The HW itself generated no Raman scattering or fluorescence noise during transmission. A complex filtering system at the end of the waveguide was thus unnecessary. In addition, the measured Raman spectra showed better signal-to-noise ratios than a conventional Raman fiber probe. The HW's suitability as a Raman fiber probe was also demonstrated. 相似文献
65.
Thermal color superconducting phase transitions in high density three-flavor quark matter are investigated in the Ginzburg-Landau approach. The effects of nonzero strange quark mass, electric and color charge neutrality, and direct instantons are considered. Weak coupling calculations show that an interplay between the mass and electric neutrality effects near the critical temperature gives rise to three successive second-order phase transitions as the temperature increases: a modified color-flavor locked (mCFL) phase (ud, ds, and us pairings) --> a d-quark superconducting (dSC) phase (ud and ds pairings) --> an isoscalar pairing phase (ud pairing) --> a normal phase (no pairing). The dSC phase is novel in the sense that while all eight gluons are Meissner screened as in the mCFL phase, three out of nine quark quasiparticles are always gapless. 相似文献
66.
Suwa Y Matsuura S Fujimori M Heike S Onogi T Kajiyama H Hitosugi T Kitazawa K Uda T Hashizume T 《Physical review letters》2003,90(15):156101
Novel atomic structures on a H-terminated Si(100)-(2x1)-H surface were found using scanning tunneling microscopy (STM). The structures are distinguishable only from Si dimers in empty-state STM images. They were observed on arsenic- and phosphorus-doped substrates, but not on boron-doped substrates. Surface density of these structures was found to be proportional to the dopant density in the substrate. First-principles calculations clarify that they are consisting of dopant pairs that are segregated from the bulk material. Hydrogen atoms attached to the dopant pair are found to flip between two positions on the surface due to a quantum effect. 相似文献
67.
Measurement Accuracy in Phase-Shifting Point Diffraction Interferometer with Two Optical Fibers 总被引:1,自引:0,他引:1
Toshiaki Matsuura Satoru Okagaki Takaaki Nakamura Yasushi Oshikane Haruyuki Inoue Motohiro Nakano Toshihiko Kataoka 《Optical Review》2007,14(6):401-405
A phase-shifting point diffraction interferometer (PS/PDI) with point sources of two single mode optical fibers has been developed,
which will be appropriate for the surface figure measurement of large aperture optics on a sub-nanometer scale. To reduce
the measurement error factors, a fiber optic plate (FOP) is used as a projection plane for interference pattern. Errors caused
by imperfection of optical alignment, such as position of point sources and tilt of FOP, are minimized by analyzing the measured
phase data with an original method. Measurement accuracy in the PS/ PDI is estimated with the interference pattern produced
by the two optical fiber sources. If inhomogeneity of the FOP and a systematic error of the PS/PDI are eliminated, the measurement
accuracy of the present system is estimated to be less than 4nm P-V and 0.7nm rms, respectively, at a measurement wavelength
of 632.8 nm. 相似文献
68.
Chandra Kanta Ghosh Anirban Ray Amarendra Patra 《Journal of heterocyclic chemistry》2001,38(6):1459-1463
The title aldehyde 1 in the presence of ammonia gives the pyridine derivatives 9‐11 respectively with acetylacetone, diethyl malonate and ethyl cyanoacetate, and ethyl (or methyl)‐l‐benzopyrano[4,3‐b]pyri‐dine‐3‐carboxylate 22 (or 23 ) with ethyl (or methyl) acetoacetate. Acetylacetone pretreated with ammonia condenses with 1 giving the fused pyridine 24 . Ammonia converts the ester 6 to the pyridine 13 or 14 . Chromic acid oxidation of 22 and 23 affords the coumarinopyridines 25 and 26 , respectively. 相似文献
69.
70.
Atmospheric plasma sprayed alumina–titania (Al2O3–13%TiO2), coated on stainless steel (XC18), were characterized. The coating structure and morphology were studied by scanning electron
microscopy. Their presented micro cracks, laminar splats. The coatings were studied by X-ray diffraction. The main phase transformation
is that of α-Al2O3 into metastable γ-Al2O3. The α-Al2O3 phase is due to the occurrence of partially melted particles Electrochemical behaviours of coatings were mainly investigated
by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.01 M [K3Fe(CN)6/K4Fe(CN)6] as a function of process parameters. Also, schematic equivalent circuit was proposed. The results were expected to facilitate
the understanding and improvement of the coating behaviours. 相似文献