نتایج جستجو برای: low intensity laser

تعداد نتایج: 1504408  

2007
H. Al-Qahtani B. S. Yilbas

Laser pulse heating of solid surface and entropy generation during the heating process are considered. Time exponentially decaying pulse is accommodated in the analysis and the laser pulse parameter (b1/b2) resulting in minimum entropy generation rate is computed. Analytical solutions for temperature rise are presented and volumetric entropy generation rate is formulated. Two laser pulses resul...

Journal: :Physical review letters 2008
S Kneip S R Nagel C Bellei N Bourgeois A E Dangor A Gopal R Heathcote S P D Mangles J R Marquès A Maksimchuk P M Nilson K Ta Phuoc S Reed M Tzoufras F S Tsung L Willingale W B Mori A Rousse K Krushelnick Z Najmudin

The dynamics of plasma electrons in the focus of a petawatt laser beam are studied via measurements of their x-ray synchrotron radiation. With increasing laser intensity, a forward directed beam of x rays extending to 50 keV is observed. The measured x rays are well described in the synchrotron asymptotic limit of electrons oscillating in a plasma channel. The critical energy of the measured sy...

2007
Rajesh S. Patel

High-power, nanosecond-pulse Q-switch laser processing has become commonplace in both existing and emerging high-tech industries. As these industries grow and mature, there is increased need for low-cost, high-quality manufacturing techniques. This translates to a need for increasingly precise and efficient laser processing capabilities. In this work, Newport/Spectra-Physics’ latest Q-switch di...

2009
Stephen D. Roberson

We detect trace residues of RDX and TNT by surface photofragmentation fragment detection in real time at ambient conditions. An infrared or visible laser generates signature, NO molecular fragments, and a second, low energy, ultraviolet laser facilitates their detection by resonance enhanced multiphoton ionization. We present the effects of pump laser wavelength, laser energy, delay timing betw...

Journal: :iranian endodontic journal 0
mehdi vatanpour department of endodontics, dental school, islamic azad university, and member of iranian center for endodontic research, tehran, iran maryam javidi department of endodontics, dental school, mashad university of medical sciences, mashad, iran mina zarei department of endodontics, dental school, mashad university of medical sciences, mashad, iran shiva shirazian private specialist in oral medicine

external root resorption may be an uncontrolled phenomenon, and the most known interventions have no effect. even progressive external root resorption may not be controlled by long term ca(oh)2 therapy. currently, there are no treatment options for vital tooth that suffer from root resorption. this invasive resorption can lead to extraction of the tooth. the use of new technologies such as low ...

Journal: :journal of lasers in medical sciences 0
massoud seifi elahe vahid-dastjerdi

low-level laser therapy (lllt) provides several benefits for patients receiving orthodontic treatment. according to some literatures, orthodontic tooth movement (otm) can be enhanced but some investigators have reported contradictory results. this article reviews the literature regarding the different aspects of the use of lllt on otm and its alterations. the general data regarding the study de...

Journal: :journal of lasers in medical sciences 0
dawood aghamohammadi department of anesthesia, tabriz university of medical sciences, tabriz,iran mohammad eidi department of anesthesia, tabriz university of medical sciences, tabriz,iran alireza lotfi department of otorhinolaryngology, tabriz university of medical sciences, tabriz, iran hamzeh hosseinzadeh department of anesthesia, tabriz university of medical sciences, tabriz,iran reza movasaghi department of anesthesia, tabriz university of medical sciences, tabriz,iran negar motighini department of anesthesia, tabriz university of medical sciences, tabriz,iran

introduction: tonsillectomy is among commonest otorhinolaryngologic surgeries. many methods have been used to control post surgical pain, but despite it, pain is still one of the problems related to this operation. recently, due to the non invasiveness of low level lasers, this modality has attracted attention. the purpose of this study is to evaluate the effects of low level laser irradiation ...

Journal: :the modares journal of electrical engineering 2010
fateme shahshahani vahid ahmadi kavous mirabbaszadeh

in this paper, the effects of reflected waves of the facets on the internal optical intensity of semiconductor dfb lasers are investigated. the uniformity of optical intensity along the cavity length is evaluated with flatness parameter. the dependence of this parameter on coupling coefficient, reflectivity and grating phase at the facets is also studied. this investigation shows that in some s...

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