The modulation of chaotic behavior in semiconductor laser with A.C coupling optoelectronic feedback has been numerically and experimentally reported. The experimental and numerical studying for the evaluation of chaos modulation behavior are considered in two conditions, the first condition, when the frequency of the external perturbation is varied, secondly, when the amplitude of this perturbation is changed. This dynamics of the laser output are analyzed by time series, FFT and bifurcation diagram.
A high power N2 laser of the three stage-Blumlein circuit designed, which consist two identical electrodes, four capacitors and three spark gaps which designed discharge geometry with minimum inductance. This system gives a maximum energy 18 mJ with a pulse time 6.65 ns and wave length 337.1 nm. The distance between spark gap terminals has large effect on the output energy. The ideal distance were 11 mm between the terminals for the first spark gap and 4 mm between the terminals for the second spark gap, the distance between the terminals of the spark gaps has a significant effect on the resulting energy, where the energy decreases when the distance between the terminals of the first and second s
... Show MoreMany researches focused on laser therapy of wound healing in different animal models due to the lack of a standard protocol in the application of such phototherapy. Objective: To study the effects of 810nm laser at a constant irradiance of 41.63 mw/cm2 and exposure (illumination) time of 5,15 minutes on wounds created on Albino mice (BALB/c).
Skin wound with elliptic shape and full thickness was created on the dorsal side of ‘45 mature male albino mice. Irradiated animals were divided into two main groups based on irradiation time, the first was irradiated for 5 min and the second for 15 min, each was subdivided into three subgroups (n=5) according to number of treatment
... Show MoreIn the last years, new non-invasively laser methods were used to detect breast tumors for pre- and postmenopausal females. The methods based on using laser radiation are safer than the other daily used methods for breast tumor detection like X-ray mammography, CT-scanner, and nuclear medicine.
One of these new methods is called FDPM (Frequency Domain Photon Migration). It is based on the modulation of laser beam by variable frequency sinusoidal waves. The modulated laser radiations illuminate the breast tissue and received from opposite side.
In this paper the amplitude and the phase shift of the received signal were calculated according to the orig
... Show MoreOne of the troublesome duties in chemical industrial units is determining the instantaneous drop size distribution, which is created between two immiscible liquids within such units. In this work a complete system for measuring instantaneous droplet size is constructed. It consists of laser detection system (1mW He-Ne laser), drop generation system (turbine mixer unit), and microphotography system. Two immiscible liquids, water and kerosene were mixed together with different low volume fractions (0.0025, 0.02) of kerosene (as a dispersed phase) in water (as a continuous phase). The experiments were carried out at different rotational speed (1180- 2090 r.p.m) of the turbine mixer. The Sauter mean diameter of the drops was determined by la
... Show MoreA theoretical model is developed to determine time evolution of temperature at the surface of an opaque target placed in air for cases characterized by the formation of laser supported absorption waves (LSAW) plasmas. The model takes into account both plasma dynamics and time variation of incident laser pulse (i.e. pulse shape or profile).Shock tube relations were employed in formulating plasma dynamics over target surface. Gaussian function was chosen in formulating the pulse profile in the present modeling
The main goal of this in vivo study was to evaluate the effect of 532nm Q-switched Nd: YAG Laser in combination with Human Serum Albumin 20% concentration (as a welding aid) on the liver tissue repair clinically, and histologically. The animals used in this study were 21 male rabbits divided into three main groups: control group (3 rabbits), conventionally treated group (9 rabbits) and Laser treated group (9 rabbits). Each two main groups (conventional and laser treated) consist of three sub-groups depending on the response evaluation at three different periods. The Laser group was treated using 532nm Q-switched Nd: YAG laser after adding human serum albumin immediately on the incised liver’s tissue. The energy of was 460mJ, and 4Hz fr
... Show MoreFour photosensitizers were used to test inhibitory effect of Helicobacter pylori bacteria using
low power helium: neon red laser radiation. Biopsies were collected from 176 patients and H. pylori were
isolated, identified and bacterial suspension was prepared. Samples of this suspension were mixed with
various low concentrations of the test sensitizer. The mixture samples were exposed to different laser
radiation doses. The samples were then inoculated and the inhibition zones were studied and compared
with their analogues of control samples. The most effective sensitizer with optimum concentration and
irradiation dose was determined. Statistical analysis of results was performed. The sensitizers' toluidine
blue and
The sample's physical characteristics and laser parameters impact the generation and characterization of Laser-Induced Plasma (LIP), which is a relevant phenomenon in many applications. We investigated the effect of laser energy on laser-induced Zn plasma characterization in this study. A Zn plasma with a repeating frequency of 6 Hz, a first wavelength of 1064 nm, a pulse duration of 10 ns, and a laser energy range of 300 mJ to 500 mJ was created using a Q-switched ND: YAG laser. The basic plasma properties, such as electron temperature and density, were estimated using optical emission spectroscopy (OES). The electrons' temperature was measured by the Boltzmann plot method, and the value of the electrons' temperature ranged from 1.6 eV
... Show MoreSpin coating technique has been applied in this work to prepared Xerogel films doped with Rhodamine 6G laser dyes. The solid host of laser dye modifies its spectroscopic properties with respect to liquid host. During the spin coating process the dye molecules suffer from changing their environment. The effects of three parameters were studied here: the spinning speed, multilayer coating and formaldehyde addition
Regional immune response with mammary gland carcinoma was
studied statistically. However, the prognostic value remains
conflicting. Thirty mice were used in this study which infected
were with mammary gland carcinoma. The tumor size of the animals
under study were measured before and after laser irradiation by using
a vernier and compared these results were with that of non irradiated
animals with laser (control group)
The aim of this study was to evaluate the effect of low level laser
therapy (LLLT) on increasing the response of immune system by
stimulating the lymph node action to decrease the cancer cell activity
and then decreasing the tumor size of an infected mice.
The results of the gross observati