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Summary form only given. An atmospheric pressure nonequilibrium argon/oxygen plasma jet assisted by the preionization of syringe needle electrode discharge is reported. With the syringe needle plasma as its pre-ionization source, the hybrid barrier-jet was shown to generate uniform discharge with a lower breakdown voltage and a relatively low gas temperature varying from 390 to 440 K, even when the vol.% oxygen in argon was up to 6%. Time-averaged optical emission spectroscopy is used to measure the plasma parameters, of which the excitation electron temperature is determined by the Boltzmann's plot method whereas the gas temperature is estimated using a fiber thermometer. Furthermore, the Stark broadening of the hydrogen Balmer H□line is applied to measure the electron density, and the simultaneous presence of comparable Doppler, van der Waals, and instrumental broadenings is discussed. It has been found that the electron densities in this argon plasma jet are on the order of 1014cm-3, and the excitation temperature, gas temperature, and electron density increase with the applied voltage. The concentration of atomic oxygen was estimated to be about in an orders of magnitude of 1017cm-3. The jet was then employed to oil removal from glass surfaces and a maximum cleaning rate of 0.1 mm/s was achieved.