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291.
Rowley JD Pierce JK Brant AT Halliburton LE Giles NC Schunemann PG Bristow AD 《Optics letters》2012,37(5):788-790
Optical rectification is demonstrated in (110)-cut ZnGeP(2) (ZGP) providing broadband terahertz (THz) generation. The source is compared to both GaP and GaAs over a wavelength range of 1150 nm to 1600 nm and peak-intensity range of 0.5 GW/cm(2) to 40 GW/cm(2). ZGP peak-to-peak field amplitude is larger than in the other materials due to either lower nonlinear absorption or larger second-order nonlinearity. This material is well suited for broadband THz generation across a wide range of infrared excitation wavelengths. 相似文献
292.
The spin polarization of photoelectrons emitted form La doped EuO was measured as a function of light energy up to hv = 11 eV, together with the quantum yield. The spectrum of spin polarization can be understood in terms of the energy level diagram of bulk EuO. 相似文献
293.
A one-fourth scale model of the large (425 m3) National Bureau of Standards reverberation room is described. This facility was constructed to carry out acoustical research at relatively low cost in a frequency range two octaves higher than that used in the larger facility. Initial experimental measurements carried out in this facility concern sound power emitted by small sources. The pure tone qualification procedure specified in American National Standard S1.21-1972 ‘Metods for the Determination of Sound Power Levels of Small Sources in Reverberation Rooms’ was carried out using computer control of the experiment. This standard is of particular interest to the international acoustical community since it is technically equivalent to ISO Documents DIS 3741 and DIS 3742. The effect of increased low frequency absorption upon room qualification was tested in the model room. Future research plans to make use of the small-scale reverberation rooms are described. 相似文献
294.
295.
Jérôme JP. Leon 《Letters in Mathematical Physics》1981,5(1):75-80
We establish a transformation which connects the potentials of the one-dimensional Dirac and Klein-Gordon operators. This transformation links the solutions of the nonlinear evolution equations solvable by means of the two inverse spectral transforms which use the Dirac and Klein-Gordon direct and inverse spectral problems. 相似文献
296.
297.
Hydrozirconation of allenes followed by in situ transmetalation to dialkylzinc leads to the formation of an allylic zinc species that, upon addition of aldimines to the reaction mixture, provides homoallylic amines in 64-85% yield. [reaction: see text] 相似文献
298.
Jay K. Kouba Janelle L. Pierce Richard A. Walton 《Journal of organometallic chemistry》1980,202(4):C105-C107
X-ray photoelectron spectroscopy has been found to provide a useful means of studying the electronic structure of the phosphorus atoms in PPh, PPh2, PPh3, PHPh and P(OMe)3 ligands in a number of polynuclear cobalt and iron complexes. 相似文献
299.
R. S. Seymour M. S. Andreaco J. Pierce 《Journal of Radioanalytical and Nuclear Chemistry》1988,123(2):529-550
Numerous and diverse mathematical methods have been used to model the full-energy photopeak (FEP) efficiency-to-energy relationship. All of the methods attempt to approximate this relationship using numerical analysis methods. Sophistication of the mathematics does not guarantee a meaningful and accurate determination of the physical relationships being modeled. This discrepancy stems from the fact that the data being modeled may suffer from spectral and nuclear effects which alter the counts in the full energy photopeak resulting from absorption and attenuation in the active volume of the diode, in the intervening materials between the detector diode and source, within the source itself, and in the shielding around the detector and source. Data must be free of these effects either as a result of acquiring the spectral data in geometries which minimize or eliminate these effects, or by pre-treatment of the net area counts to correct for these effects. If these corrections are not possible, then the choice of mathematical fitting method should be constrained to provide results which are consistent with physical-theoretical considerations of the energy-efficiency relationship being modeled. If possible, the method chosen should also provide a meaningful estimate of the uncertainty associated with the approximation of this function. 相似文献
300.
The rate constant for the formation of H+5 (D+5) at (86 ± 3) °K by the three-body process has been determined (k3(H) = (2.16 ± 0.10) × 10?28 × 10?28 cm6/molecule2 sec and k3(D) = (1.47 ± 0.20) × 10?28 cm6/molecule2 sec) in a high pressure mass spectrometer. Comparison of this result with published rate data at 300 °K indicates the reaction has an apparent activation energy of ?1.5 kcal/mole. 相似文献