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101.
Junji Yamauchi Takashi Ando Yasuhiro Akimoto Hisamatsu Nakano 《Fiber and Integrated Optics》1996,15(4):353-363
A wavelength filter consisting of single-mode and few-mode fibers is investigated numerically. A simple finite-difference beam-propagation method, in which a transparent boundary condition can be imposed, is developed for circularly symmetric waveguides. After confirming the validity of the numerical method by the mode-mismatch loss, we calculate the propagating field in the fiber wavelength filter, in which interference between LP01, and LP02 modes occurs. To improve the filtering operation, a depressed-index fiber is employed for the few-mode fiber. The effects of the radius and refractive index of the depressed section on the transmission power are revealed and discussed. Power is suppressed to less than 0.1% at 1.3 μm, while maintaining power transmission of more than 85% at 1.55 μm. It is also found that the filtering operation shifts to higher wavelengths as the input power is increased when we choose a self-focusing nonlinear material in the depressed section. 相似文献
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104.
Takayoshi Kobayashi 《Optics Communications》1979,28(1):147-149
The spectrum of the picosecond broad-band light generated by focusing picosecond laser light into a cell containing phosphoric acid was measured with an OMA. The dependence of the spectrum on the pumping energy was studied. It is noticed that great care must be taken when the broad-band continuum is used as an interrogation beam for picosecond absorption spectroscopy. 相似文献
105.
Mori S Endo M Furukawa S Sunaoka M Nonaka H Ishii T Ikehira H 《Magnetic resonance imaging》2005,23(5):691-694
We developed a high radiation sensitive polymer gel by modifying the amounts of the gel components and the temperature for the gel preparation. We evaluated its relaxation time linearity against dose and compared the measured dose distribution with the calculated one. For the relaxation time-dose linearity, irradiations were carried out with a linear accelerator using 6 MV photons and doses ranging from 0-5.0 Gy. The relationship between dose and R(2) value (reciprocal of T(2) relaxation time) was measured and it had good linearity over a wide range (0.3-5 Gy). The measured dose distributions were in good agreement with calculated ones. Since the present gel has higher sensitivity and it is synthesized more easily at lower cost than conventional polymer gels, we expect to see improved three-dimensional (3D) dosimetry using it. 相似文献
106.
Nakano K Suemura N Yoneda K Kawata S Kaizaki S 《Dalton transactions (Cambridge, England : 2003)》2005,(4):740-743
Two series of pyrazolato bridged dinuclear NCS and NCBH3 diiron(II) complexes with various types of 3- or 4-substituted pyridines, [{Fe(NCS or NCBH3)(X-py)}2(mu-bpypz)2], were prepared and their variable-temperature magnetic susceptibilities were measured. There were found linear correlations of the spin-crossover temperatures Tc not only between the NCS and NCBH3 complexes with the corresponding substituted pyridines, but also between the Tc and the Hammett constants, supporting the electronic substituent effect of the coordinated pyridine rather than a steric effect. The ligand field and the interelectronic repulsion parameters together with the thermodynamic data and/or cooperativity factor were discussed in relation with their spin-crossover behavior. 相似文献
107.
Ultrafast charge resonant (CR) dynamics between two molecules in a dimer system has been studied theoretically and experimentally using 6-fs laser pulses and a thin film of amorphous-phase phthalocyanine tin(IV) dichloride (SnPc). The modulation of the absorbance change in the bleaching spectral range of the CR absorption band was analyzed to obtain the amount of charge resonantly transferred back and forth by a dimeric vibration induced by photoexcitation. The modulation can be explained in terms of a periodic change in the cross section and a periodic energy shift, where both are induced by the change in the overlap integral caused by the accordion-type intermolecular vibration. The associated change in distance between two molecules with the intermolecular vibration was estimated to be 0.09 A, which corresponds to 2.5% of the mean distance between the two SnPc molecules in the dimeric system. 相似文献
108.
We demonstrate the efficiency of the optical poling process that depends on the CE phase-controlled quantum interference. For the experiment we employed our noncollinear optical parametric amplifier system for the self-stabilization of the CE phase, with the f-to-2f spectral interferometry system to control the CE phase. 相似文献
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A Reformatsky-type aldol reaction of alpha-chloroketones with aldehydes has been achieved using reactive barium as a low-valent metal in THF; this one-pot process is more effective for obtaining the desired beta-hydroxy ketones in high yields than the stepwise process in which barium enolates are prepared prior to the reaction with aldehydes. 相似文献