Carbon laser system

Ku, R. T., E. D. Hinkley, and J. O. Sample. Long-path monitoring of atmospheric carbon monoxide with a tunable diode laser system. Appl. Optics 14 854-861, 1975. 

Bigger clusters have been formed, for instance, by the expansion of laser evaporated material in a gas still under vacuum. For metal-carbon cluster systems (including M C + of Ti, Zr and V), their formation and the origin of delayed atomic ions were studied in a laser vaporization source coupled to a time-of-flight mass spectrometer. The mass spectrum of metal-carbon cluster ions (TiC2 and Zr C j+ cluster ions) obtained by using a titanium-zirconium (50 50) mixed alloy rod produced in a laser vaporization source (Nd YAG, X = 532 nm) and subsequently ionized by a XeCl excimer laser (308 nm) is shown in Figure 9.61. For cluster formation, methane ( 15% seeded in helium) is pulsed over the rod and the produced clusters are supersonically expanded in the vacuum. The mass spectrum shows the production of many zirconium-carbon clusters. Under these conditions only the titanium monomer, titanium dioxide and titanium dicarbide ions are formed. 

Ku, R. T., Hinkley, E. D., and Sample, J. O. "Long-Path Monitoring of Atmospheric Carbon Monoxide with a Tunable Diode Laser System." Applied Optics 14 (1975) 854-61. 

Recent work on the carbon dioxide system shows another unusual high-pressure behaviour. Raman spectra of carbon dioxide show that CO2 molecules remain the basis of the phases to more than 40 GPa at temperatures below a few hundred Kelvin [52]. These results, however, do not mean that the molecular crystals are the stable phases indeed, recent studies of the combustion of carbon at high pressures by Yoo et al [53] reach another conclusion. They initiated combustion of a mixture of carbon and oxygen at pressures between 7 and 13 GPa by heating the carbon with a Nd YAG laser, quenching the products to ambient temperature under pressure and recording their Raman spectra. As well as features of unreacted O2 and CO2 in some samples,... 

The carbon dioxide laser has greater productivity than the excimer laser or the UVYAG laser when used to generate via holes larger than 60 /rni in diameter however, it cannot drill through copper foil directly. As a result, a black surface treatment is required on the thin copper foils before the laser operation. (See Fig. 63.6) Comparisons of the technical capabihties of these micro via processes of the laser systems are shown in Table 63.4. 

The excimer laser process, like the UV YAG laser system, minimizes the potential for thermal damage on very thin flying leads. The carbon dioxide laser generates a remarkable amount of heat. The beam power density of the laser must be controlled carefully in order to process 18-fjm copper with high-density flying leads narrower than 100 fjm wide. 

Synthesis of silica-carbon nanotube composite materials and their application for laser systems. Mater. Sci. Eng., 38, 012053. 

No information was found on the transformation of diisopropyl methylphosphonate in the atmosphere. Based on the results of environmental fate studies of diisopropyl methylphosphonate in distilled water and natural water, photolysis (either direct or indirect) is not important in the transformation of diisopropyl methylphosphonate in aquatic systems (Spanggord et al. 1979). The ultraviolet and infrared laser-induced photodegradation of diisopropyl methylphosphonate in both the vapor or liquid phase has been demonstrated (Radziemski 1981). Light hydrocarbon gases were the principal decomposition products. Hydrogen, carbon monoxide (CO), carbon dioxide (C02), and water were also detected. 

The samples were collected from the cathodes 2.5 cm away from the current collector tab, washed in pure dimethyl carbonate (DMC), and soaked in DMC for 30 minutes after removal from Li-ion cells inside an argon-filled glove box. This procedure removed electrolyte salt from the electrode to prevent its reaction with air and moisture. An integrated Raman microscope system Labram made by ISA Groupe Horiba was used to analyze and map the cathode surface structure and composition. The excitation source was an internal He-Ne (632 nm) 10 mW laser. The power of the laser beam was adjusted to 0.1 mW with neutral filters of various optical densities. The size of the laser beam at the sample was 1.2 pm. 

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