MEASUREMENTS OF RAMAN CROSS SECTIONS FOR VARIOUS GASES IN THE POLLUTED ATMOSPHERE BY MEANS OF PULSED LASER-RAMAN AND PULSE-GATED PHOTON COUNTING METHODS

$^{1}$ H. Inaba and T. Kobayasi, Nature 224, 170 (Oct. 1969) $^{2}$ T. Kobayasi and H. Inaba, Appl. Phys. Letters 17, 139 (Aug. 1970); Proc. of the IEEE. 58, 1568 (1970). $^{3}$ H. Inaba and T. Kobayasi, Paper presented to 26th Symposium on Molecular Structure and Spectroscopy N4, Columbus, Ohio, June 14-18, 1971. $^{4}$ W. F. Murphy, W. Holzer and H. J. Bernstein, Appl. Spectroscopy 23, 211 (1969). $^{5}$ D.G. Fouche and R.K. Chang, Appl. Phys. Letters 18, 579 (June 1971).""Author Institution: Research Institute of Electrical Communication, Tohoku UniversityFeasibility and potentiality of the laser radar system which detects the Raman-shifted backscattering, either in non-resonant or resonant nature, from chemical contents of atmospheric pollutants to identify and to monitor remotely their concentrations have been $demonstrated.^{1-3}$ However, for the precise measurement of species concentration, the knowledge on the Raman scattering cross sections is always required. This paper presents the measured result and their comparison of the Raman cross sections of various molecules present in the atmosphere such as $NO_{2}, NO, SO_{2}, CO_{2}, CO, O_{2}, H_{2}$ relative to that of $N_{2}$ as a reference gas. We employed primarily a molecular nitrogen laser with 10mW average power at 3371 {\AA}, 20 kW peak power of 10 nsec duration and a repetition rate of 50 Hz. Recently, we have succeeded in the operation of transverse excitation atmospheric (TEA) nitrogen laser at 3371 {\AA} which is applicable to the field-use and also to the laboratory experiments. The Raman scattered radiation was observed in a direction perpendicular to the linearly polarized plane of the incident laser beam. The signal was processed by the pulse-gated photon counting method synchronized with the repetitive laser pulse, which is valuable for detecting extremely weak light signals. The accuracy of our measured cross sections is within 10\% and their values were found to agree well with the pre-laser result by Murphy et $al.^{4}$ and the laser result by Fouche et $al.^{5}$ for several gases. It is noteworthy that $NO_{2}\nu_{1}$ band has 15 times and $\nu_{2}$ band has 7.2 times larger cross section than that of $N_{2}$, due possibly to resonance Raman effect at 3371 {\AA}

SPECTROSCOPIC REMOTE-SENSING OF MOLECULAR CONSTITUENTS IN THE ATMOSPHERE BY LASER-RADAR TECHNIQUES BASED ON OPTICAL SCATTERING PHENOMENA

$^{1}$H. Inaba and T. Kobayasi, Nature, 224, 170, (1969). $^{2}$T. Kobayasi and H. Inaba, Appl. Phys. Letters, 17, 139, (1970). $^{3}$H. Inaba and T. Kobayasi. Invited paper to the Sixth International Quantum Electronics Conference, Kyoto, Japan, September 1970. $^{4}$T. Kobayasi and H. Inaba. Proceedings of IEEE., 58, 1568, (1970).""Author Institution: Research Institute of Electrical Communication, Tohoku UniversityThe usefulness of Raman spectroscopy, which is so far recognized as a complementary technique to infrared spectroscopy, can be extended to include various new fields which are unique to itself. The laser-Raman radar scheme detecting the Raman backscattered echoes has been $proposed^{1}$ and confirmed experimentally by the present $authors^{2-4}$, which is capable of measuring remotely the number density of molecular constituents as well as their species existing not only in the ordinary but also in the polluted atmosphere. This paper wishes to report the operational performance and the experimental results, so far obtained, of our laser-Raman radar as a completely single-ended system for the chemical analysis of the real atmosphere. An alternative method, which utilizes a frequency-tunable dye laser with high repetition rate of pulsed operation is also developed to investigate the resonance spectroscopic effects of a variety of molecules and atoms contained in the lower and upper atmosphere. These effects include the fluorescence and the resonance scatterings along with the resonance Raman scattering, and are expected to improve significantly the sensitivity and the range capability for the constituent analysis of our environmental air

The first observation of O2− generation in in situ lungs of rats treated with drugs to induce experimental acute respiratory distress syndrome

AbstractTo investigate O2− generation in in situ lungs of rats treated with drugs to induce experimental acute respiratory distress syndrome, phorbol myristate acetate (PMA) or endotoxin were injected into rats, who had been continuously infused with 2(methyl-6-[p-methoxyphenyl]-3,7-dihydro-imidazo[l,2-α]pyrazin-3-one (MCLA) and the chemiluminescence in in situ lung was detected by a sensitive photon counter. In PMA-treated rats, two phases of chemiluminescence over non-specific chemiluminescence were observed. The first phase luminescence was sensitive to Cu-Zn superoxide dismutase, while the second phase chemiluminescence was less sensitive to Cu-Zn Superoxide dismutase. Similar chemiluminescence was detected in the rats treated with endotoxin instead of PMA, but not in neutropenic rats