Satelitske vrpce u kvazistatičkim krilima Tl i In rezonantnim linijama proširenih pomoću Hg

Using a high pressure metal-halide discharge lamps, we have measured the spectral positions of the satellite bands in the wings of Tl 535.1 nm and 377.6 nm, and In 451.1 nm and 410.2 nm resonance lines. The satellite bands in the red wings are attributed to the TlHg or InHg excimers, and those appearing in the near blue wings to the Tl2, and In2 molecules. Using the Abel inversion procedure, we obtained the relevant spatial temperature and spectral intensities distributions, from which we have concluded that the red satellite bands are due to the bound portion of the TlHg or InHg excited potentials.Upotrebivši visokotlačne metal–halogene izbojne svjetiljke, izmjerili smo spektralne položaje satelitskih vrpca rezonantnih linija Tl 535.1 nm i 377.6 nm, te In 451.1 nm i 410.2 nm. Satelitske vrpce u crvenim krilima pripadaju TlHg ili InHg ekscimerima, a one koje se pojavljuju u plavim krilima pripadaju Tl2 i In2 molekulama. Koristeći postupak Abelove inverzije zaključujemo da crvene satelitske vrpce pripadaju vezanom dijelu TlHg ili InHg pobuđenih potencijalnih krivulja

Bošković’s Water-filled Telescope and Lopašić’s Explanation

U osamnaestom stoljeću Bošković je želio iznaći da li je svjetlo val ili čestica. Stoga je sugerirao pokus u kojemu treba napuniti dalekozor vodom i time pronaći promjene iznosa aberacije zvijezde. Stotinu godina kasnije Sir Airy (1871.) je izveo eksperiment, ali s negativnom rezultatom. Lopašić je to objasnio pomoću Einsteinova principa specijalne relativnosti.In 18th century Bošković tried to find out if light is wave or corpuscule. Therefore, he suggested to fill a telescope with water to test alteration in the amount of stellar aberration. Hundred years later, Sir Airy (1871) had done this experiment, but with negative result. Lopašić had explained it by means of Einstein’s principle of the special relativity

Satelitske vrpce u kvazistatičkim krilima Tl i In rezonantnim linijama proširenih pomoću Hg

Using a high pressure metal-halide discharge lamps, we have measured the spectral positions of the satellite bands in the wings of Tl 535.1 nm and 377.6 nm, and In 451.1 nm and 410.2 nm resonance lines. The satellite bands in the red wings are attributed to the TlHg or InHg excimers, and those appearing in the near blue wings to the Tl2, and In2 molecules. Using the Abel inversion procedure, we obtained the relevant spatial temperature and spectral intensities distributions, from which we have concluded that the red satellite bands are due to the bound portion of the TlHg or InHg excited potentials.Upotrebivši visokotlačne metal–halogene izbojne svjetiljke, izmjerili smo spektralne položaje satelitskih vrpca rezonantnih linija Tl 535.1 nm i 377.6 nm, te In 451.1 nm i 410.2 nm. Satelitske vrpce u crvenim krilima pripadaju TlHg ili InHg ekscimerima, a one koje se pojavljuju u plavim krilima pripadaju Tl2 i In2 molekulama. Koristeći postupak Abelove inverzije zaključujemo da crvene satelitske vrpce pripadaju vezanom dijelu TlHg ili InHg pobuđenih potencijalnih krivulja

Nitrogen laser beam interaction with copper surface

The ultraviolet and visible spectra of plasmas produced by N_2-laser radiation focused onto a copper target in air and in vacuum have been recorded photographically. The nitrogen laser beam (α = 337 nm) had a maximum energy density of 1.1 J/cm^2, the pulse duration was 6 ns, and the repetition rate 0.2 Hz. The measured electron temperature was 15000 K (±30%) in air and 13000 K (±50%) in vacuum and the electron densities were 6.5×10^17 cm^-3 (±60%) and 3.0×10^17 cm^-3 (±60%), respectively. The irradiated surface in air and in vacuum was studied employing a metallographic microscope. In vacuum, the droplets were created and expulsed at the crater edges. Their formation is explained by the hydrodynamical model. They were formed in a time interval which is about two times shorter than the duration of the laser pulse. In air, droplets were also formed. The weight loss from the Cu-crater in vacuum was about 0.3×10^-4 µmole/pulse, in air it was about three times less

Djelovanje snopa dušikovog lasera na površinu bakra

The ultraviolet and visible spectra of plasmas produced by N2-laser radiation focused onto a copper target in air and in vacuum have been recorded photographically. The nitrogen laser beam (α = 337 nm) had a maximum energy density of 1.1 J/cm2, the pulse duration was 6 ns, and the repetition rate 0.2 Hz. The measured electron temperature was 15000 K (±30%) in air and 13000 K (±50%) in vacuum and the electron densities were 6.5×10^17 cm^-3 (±60%) and 3.0×10^17 cm^-3 (±60%), respectively. The irradiated surface in air and in vacuum was studied employing a metallographic microscope. In vacuum, the droplets were created and expulsed at the crater edges. Their formation is explained by the hydrodynamical model. They were formed in a time interval which is about two times shorter than the duration of the laser pulse. In air, droplets were also formed. The weight loss from the Cu-crater in vacuum was about 0.3×10^-4 μmole/pulse, in air it was about three times less.Snopom iz N2-lasera, fokusiranim na površinu bakra u zraku i vakuumu, proizvodila se plazma. Ultraljubičast se i vidljiv spektar plazme snimao na film pomoću kvarcnog spektrografa. Impulsi iz lasera (λ = 337 nm) imali su najveću gustoću energije od 1.1 J/cm2, trajanje 6 ns i učestalost 0.2 Hz. Izmjerile su se elektronske temperature od 15000 K (±30%) u zraku i 13000 K (±50%) u vakuumu, a elektronske gustoće bile su 6.5 x 10^17 cm^-3 (±60%) odnosno 3.0 x 10^17 cm^-3 (±60%). Pomoću metalografskog mikroskopa proučavale su se površine ozračene u zraku i vakuumu. U vakuumu su oko rubova kratera nastajale kapljice u vremenu oko pola trajanja laserskog impulsa, i one su padale oko kratera. Njihovo se stvaranje objašnjava hidrodinamičkim modelom. I prilikom ozračivanja u zraku izbacivale su se kapljice. Izbačena masa iz kratera u bakru je u vakuumu iznosila oko 0.3×10^-4 μmola/impulsu, a oko trećinu toga u zraku

Djelovanje dušikovog lasera na površinu titana

Solid titanium target was irradiated with a N2 laser beam of a maximal energy density of 1.1 J/cm2 per pulse and of a duration of 6 ns. The plasma, formed near the titanium surface, was analyzed by emission spectroscopy, and the irradiated Ti surface was studied by a metallographic microscope. The results of both investigations reveal the influence of resonant absorption of the laser radiation by the generated plasma. The plasma is dense and strongly ionized, with an electron density of 1.5×1018 cm-3 and electron temperature of 2.7 eV. The surface heating was found to be several times more efficient than in the cases when resonant absorption is absent. Most of the observed surface patterns appear to be caused by nonuniform surface heating and a very rapid cooling. The other features are interpreted as a possible consequence of plasma-hot surface interactions.Meta od titana ozračena je snopom iz N2 lasera maksimalne gustoće energije 1,1 J/cm2 po impulsu trajanja 6 ns. Plazma nastala uz površinu titana analizirana je emisijskom spektroskopijom, a ozrčena površina titana proučavana je metalografskim mikroskopom. Oba istraživanja ukazuju na važnost rezonantne apsorpcije laserskog zračenja u stvorenoj plazmi. Plazma je gusta i jako ionizirana, s elektroskom gustoćom 1, 5 × 1018 cm −3 i elektronskom temperaturom od 2.7 eV Zagrijavanje površine je višestruko djelotvornije nego u slučajevima kada nema rezonantne apsorpcije. Najveći dio površinskih oblika čini se uzrokovanim nejednolikim zagrijavanjem površine i vrlo naglim hlađenjem. Druge odlike se tumače kao posljedica uzajamnog djelovanja plazme s vrućom površinom

Djelovanje snopa dušikovog lasera na površinu bakra

The ultraviolet and visible spectra of plasmas produced by N2-laser radiation focused onto a copper target in air and in vacuum have been recorded photographically. The nitrogen laser beam (α = 337 nm) had a maximum energy density of 1.1 J/cm2, the pulse duration was 6 ns, and the repetition rate 0.2 Hz. The measured electron temperature was 15000 K (±30%) in air and 13000 K (±50%) in vacuum and the electron densities were 6.5×10^17 cm^-3 (±60%) and 3.0×10^17 cm^-3 (±60%), respectively. The irradiated surface in air and in vacuum was studied employing a metallographic microscope. In vacuum, the droplets were created and expulsed at the crater edges. Their formation is explained by the hydrodynamical model. They were formed in a time interval which is about two times shorter than the duration of the laser pulse. In air, droplets were also formed. The weight loss from the Cu-crater in vacuum was about 0.3×10^-4 μmole/pulse, in air it was about three times less.Snopom iz N2-lasera, fokusiranim na površinu bakra u zraku i vakuumu, proizvodila se plazma. Ultraljubičast se i vidljiv spektar plazme snimao na film pomoću kvarcnog spektrografa. Impulsi iz lasera (λ = 337 nm) imali su najveću gustoću energije od 1.1 J/cm2, trajanje 6 ns i učestalost 0.2 Hz. Izmjerile su se elektronske temperature od 15000 K (±30%) u zraku i 13000 K (±50%) u vakuumu, a elektronske gustoće bile su 6.5 x 10^17 cm^-3 (±60%) odnosno 3.0 x 10^17 cm^-3 (±60%). Pomoću metalografskog mikroskopa proučavale su se površine ozračene u zraku i vakuumu. U vakuumu su oko rubova kratera nastajale kapljice u vremenu oko pola trajanja laserskog impulsa, i one su padale oko kratera. Njihovo se stvaranje objašnjava hidrodinamičkim modelom. I prilikom ozračivanja u zraku izbacivale su se kapljice. Izbačena masa iz kratera u bakru je u vakuumu iznosila oko 0.3×10^-4 μmola/impulsu, a oko trećinu toga u zraku

Study of laser-produced plasmas from boron, carbon and boron-carbide targets

Spectroscopic investigations were made on plasma clouds created by 20 ns, 3 J ruby laser pulses impinging perpendicularly onto targets of boron carbide, carbon and boron. The irradiance on the targets was about 132 GW cm^-2. Time-resolved spectra of plasmas in the region of wavelength from 16 to 32 nm were observed at a distance of 1 mm from the targets. The maximum electron temperatures were about 60 eV in the case of carbon and boron targets, and about 45 eV in the case of boron-carbide target. Laser evaporation from carbon occurred directly from the solid state (sublimation), and in the case of a boron and boron-carbide melting was observed as an intermediate state

Površina silicija ozračena dušikovim laserskim zračenjem

Monocrystalline silicon target was irradiated with a nitrogen laser beam (λ = 337 nm, maximum energy density 1.1 J/cm2, pulse duration 6 ns and repetition rate 0.2 Hz). The plasma formed at the silicon surface was observed spetroscopically in air (ne = 3×1018 cm-3, Te = 18 500 K) and in vacuum (ne = 6.5×1017 cm-3, Te = 16 000 K). The irradiated surface in vacuum was studied by a metallographic microscope. Droplets were created at crater edges. Their formation is explained by the hydrodynamical sputtering model.Monokristalni silicij se ozračivao snopom iz dušik ovog lasera (λ = 337 nm, maksimalna snaga 1.1 J/cm2 , trajanje pulsa 6 ns i frekvencija 0.2 Hz). Plazma nastala na površini silicija se promatrala spektroskopski u zraku (ne = 3 = 1018 cm 3 , Te 18500 K) i u vakuumu (ne = 6 ¬ 5 = 1017 cm 3 , Te = 16000 K). Površina ozračena u vakuumu se proučavala pomoću metalografskog mikroskopa. Opazile su se kapljice oko ruba udubine na siliciju. Nastajanje kapljica se tumači hidrodinamičkim modelom

Površina silicija ozračena dušikovim laserskim zračenjem

Monocrystalline silicon target was irradiated with a nitrogen laser beam (λ = 337 nm, maximum energy density 1.1 J/cm2, pulse duration 6 ns and repetition rate 0.2 Hz). The plasma formed at the silicon surface was observed spetroscopically in air (ne = 3×1018 cm-3, Te = 18 500 K) and in vacuum (ne = 6.5×1017 cm-3, Te = 16 000 K). The irradiated surface in vacuum was studied by a metallographic microscope. Droplets were created at crater edges. Their formation is explained by the hydrodynamical sputtering model.Monokristalni silicij se ozračivao snopom iz dušik ovog lasera (λ = 337 nm, maksimalna snaga 1.1 J/cm2 , trajanje pulsa 6 ns i frekvencija 0.2 Hz). Plazma nastala na površini silicija se promatrala spektroskopski u zraku (ne = 3 = 1018 cm 3 , Te 18500 K) i u vakuumu (ne = 6 ¬ 5 = 1017 cm 3 , Te = 16000 K). Površina ozračena u vakuumu se proučavala pomoću metalografskog mikroskopa. Opazile su se kapljice oko ruba udubine na siliciju. Nastajanje kapljica se tumači hidrodinamičkim modelom