ftr-raman spectra of human dental enamel, both laser-irradiated and untreated, are reported. spectra are compared with hydroxyapatite. it is evident that unlike the co2 laser, the nd/yag laser does not induce any chemical change in dental enamel.

a quantum theory of a two and three-level laser with injected atomic coherence is developed by using a density operator method, to the best of our knowledge, for the first time. the initial atomic coherence plays an essential role. at steady state, the equation of motion for the density operator yields to exhibit laser without inversion and a phase locking but no threshold for the laser field. ...

the modulation response, relative intensity noise and frequency noise characteristics of qd lasers are investigated theoretically, in presence of an additional optical pumping. it is revealed that the modulation response of qd laser enhances under additional optical beam. by small signal analysis of the carriers' and photons' rates, it is proposed that by injecting excess carriers to ...

In the present work,MoS2 decorated graphene nanocomposite powders were synthesized by laser scribing method.Theobtainedflexible light-scribed graphene/MoS2composites are very suitableas micro-supercapacitors and thus their performance was evaluated at different concentrations.The effect of laser scribing process to reducegraphene oxide (GO) was investigated. The GO/MoS2composite wassynthesized ...

Cadmium and mercury have a risk of disturbing the balance in ecosystem. Cd(II) is accumulated in soil and living system organism, it is easily absorbed by plants, through their root system and by leave [1]. Acid reaction of soil increases its mobility and availability. It remains in tissues for a relatively long time and is accumulated in vital organs especially in kidney and liver [2]. Contami...

Oxidative stress plays a vital role in dopaminergic neurodegeneration of Parkinson’s disease (PD). However, an antidiabetic drug, pioglitazone had shown a positive effectagainst oxidative stress to treat nervous unrest. Objective of this study is to evaluate the protective effect of Pioglitazone (25mg/kg/p.o) against 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice model of PD. The PD i...

We present a novel slanted faces of thin-disk composite Yb:YAG YAG laser which is side-pumped by four non-symmetric hollow- ducts. The pump light distribution in the disk is modeled by using Monte-Carlo ray tracing method. The temperature distribution inside the crystal is calculated by taking into account either the concentration of Yb+3 ion or the different transmission of laser output coupl...

Seventeen two-photon transitions for neon have been observed in the 580- 635 nm spectral region for use in the spectroscopic study of its higher excited levels, which are not accessible by one-photon absorption. To compare the two and one-photon absorption signals originating from the same lower level, an effort was made to record single-photon optogalvanic spectrum in the available wavele...