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91.
The cavity length of an internal-mirror HeNe laser was controlled using a thin film heater coated on the tube. The response speed was about ten times higher than that of the usual tube wound with a ribbon heater. The high response speed brought two merits in frequency stabilization of the laser; one was improvement of stability in the short time region and the other was the realization of a thermal modulation method, by which the cavity was stabilized at Lamb's dip.  相似文献   
92.
To investigate the mechanism of the stimulation and quenching of the green luminescence in ZnS: Cu, Al phosphors by infrared (IR) light of 0.7–1.5 μm, stimulation and quenching spectra, IR effects on time-resolved emission spectra, and IR-induced photoconductivity are measured at 4.2 K, 77 K, and room temperature. Both the stimulation and quenching are caused by the IR transitions ascribed to excited copper acceptors. It is concluded that the stimulation is induced by the process in which holes produced by IR light migrate among copper acceptors, so that the statistical distribution of the intrapair separations of excited copper-aluminum pairs are changed to shorter distances. It is found that at low temperatures the holes migrate from one copper acceptor to another without being thermally released to the valence band. It is confirmed that the quenching is caused by the recombination of holes released to the valence band with electrons in the conduction band via some kind of nonradiative recombination centers.  相似文献   
93.
Summary Stability constants of 2-mercaptohistamine (2-MH) with a number of transition metal ions were determined by a potentiometric titration method and the coordination mode of (2-MH) metal complexes were thereby characterized. With MnII, Fell, CoII, and NiII, coordination occurred through both the imidazole-nitrogen and amino groups, while with ZnII, CdII, PbII, and HgII, both thiolate and amino groups, contribute to the coordination. in the 2-MH copper complex, polymer formation is suggested on the basis of visible absorption and e.p.r. spectra.  相似文献   
94.
The dye-sensitized photo-oxygenation of 1,3-dimethylindole in the presence of aldehydes initially generates a zwitterionic peroxide which condenses with the carbonyl function to give the corresponding cis-fused 1,2,4-trioxanes. Acetaldehyde gives a pair of diastereomers, one of whose structures was determined by X-ray analysis (cis,cisisomer), whereas pivaladehyde gives only the cis,cis diastereomer.  相似文献   
95.
96.
The complete structure of a unique tricyclic sesterterpene, stellatic acid, was established by X-ray diffraction of its p-bromophenacyl ester.  相似文献   
97.
98.
Methyleneimine was detected in the gas phase by a moderately high resolution infrared spectrometer as one of the intermediate species produced by a pyrolysis of amines. Observed vibrational frequencies of some isotopic derivatives have been combined with the ab initio values to reach a most reliable force constants set. Some other spectroscopic parameters, involving geometrical parameters and dipole moment derivatives, have also been calculated ab initio and compared with the observation. Its half-life in our experimental apparatus was about 10 min, which is much longer than the previously reported values, 0.1 or 10 sec.  相似文献   
99.
Photoluminescence of aSixC1?x:H (x~0.2) is studied with a particular interest on the localization of carriers. Taking the polarization memory of luminescence as a probe, we clarify the localized character of photo-generated carriers as functions of excitation photon energy, emitted photon energy, temperature and time. The picosecond time-resolved measurement of the polarization memory is shown useful to study dynamical relaxation processes of carriers in disordered systems.  相似文献   
100.
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