[en] The effect of self-phase-modulation and cross-modulation of two waves in double-core tunnel-coupled optical fibers have been investigated. It was shown that these effects considerably exert the energy exchange between the modes of the cores both cw regime of the optical fiber excitation and in the pulse one. The nonlinear dynamics of the pulses in different regimes of guided modes excitation is also investigated. 11 refs

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[en] On the basis of 'cone' jet-algorithm, a Monte Carlo study of the properties of (mini) jets in high energy hadron-hadron collisions is carried out. Using the 'jetty frame', in which the momentum of jet is chosen as Z axis, the distributions of physical quantities inside jets-multiplicity, pseudorapidity, azimuthal angle and transverse momentum are obtained. The pseudorapidity distribution is asymmetric, concentrating in the forward direction, which means that all the particles in the jet are moving forward in the direction of the total momentum of jet. This is further proved by a particle-momenta plot in the axial coordinate which shows that the jets look like sharp arrows with small forward-pointing feathers at the ends. The transverse momentum distribution for the event sample with respect to the direction of incident hadrons deviates from an exponential distribution considerably, in consistent with the production of (mini-) jets, while that inside jets with respect to the jet axis is basically an exponential. This means that the production of (mini-) jets is hard process, while the development of jets is basically soft. These results show that 'cone algorithm' is an effective method for the study of hard and semi-hard processes in high energy hadron-hadron and relativistic heavy ion collisions. It is found through the comparison of the distributions in jetty events and no-jet events that E_t = 2 GeV is a more reasonable cut for the 'cone algorithm' in finding jets

[en] A vertical calibration system with the error of about +- 15 μm for the newly eight BPMs is described here, which has been developed for the upgrade of the injection system in NSRL phase II project. A data procession to calibrate the BPM and the error calculation methods for fitting of the electric field as well as the calculating result are also presented. A commercial available Bergoz BPM Module, which works on heterodyne receiving with up tp 75dB dynamic range and 1 μm resolution, is introduced. With the calibration system and the data procession methods, the authors have completed the calibration and the inspection of the quality for newly developing eight BPMs

[en] Since 1945 considerable information has been documented about radiation accidents with significant overexposure to radiation. Most of these accidents occurred early in the development of nuclear energy. Some were criticality accidents and at experimental reactors. Although the incidence of radiation accidents in nuclear facilities has decreased considerably over the years, the number of such accidents elsewhere has risen. Several accidents have affected members of the public. Some resulted in deaths when control was lost over high strength sources, which, unrecognized for what they were, ended up in the public domain

[en] The Chernobyl accident in 1986 arose much concern throughout the world regarding the detection of contamination, control of contaminated food, related legislation and environmental monitoring. In Egypt, the environmental radioactivity monitoring program involves the establishment of a radiation monitoring network stations for continuous monitoring of ambient gamma radiation levels in the air, water, aerosols, dust particles and conventional gas pollutants. The network consists of 42 field stations for gamma monitoring of air, 14stations for beta aerosols and 15 stations for conventional pollutants. soil samples adjacent to the stations distributed all over the Egyptian territories have been collected and analyzed by gamma spectrometry. The natural radionuclides K40, U-238 series Th-232 series and the global fallout Cs-137 are found in all the collected samples. The absorbed dose rates are calculated and presented