Influence Of Radiation Sources Research Articles

Influence of Electromagnetic Fields by Electronic Implants in Medicine

Influence of electromagnetic field (EMF) from mobile phone by electronic implants used to substitute non-functional parts of human body is analyzed. Minimal distance from radiation source published in user manuals of electronic devices (implants) is 15 cm. There is presented numerical simulation, where influence of radiation source on electronic implant is proved. Ill. 5, bibl. 10 (in English, summaries in English, Russian and Lithuanian).

Design and Shielding Effectiveness of Electromagnetic Shielding Textiles

.In order to design better anti-radiation and electromagnetic shielding fabric and the clothing and makes it maintained better of electromagnetic shield effectiveness, the influence of radiation source, radiation distance, anti-electromagnetic radiation material, fabric structure, gap size, holes area, clothing exposed area as well as the tunnel effect and so on the fabric radiation protection performance were comprehensively discussed in this article. As well, according to these influence factor analysis the regular conditions that the electromagnetic shielding fabric and garment design should be meet. The analysis result indicated that the shielding effectiveness of the fabric was decreased with the increase of the radiant frequency, the fabric slit size, the hole area and enhanced with the growing of the metal content, the organizational structure close degree as well as the radiation distance.In the case of the equal shielding effect, the bigger exposed area leads weaker electromagnetic shielding effectiveness and if the exposed area oversize can cause the shield effect vanished. Also the clothing shield potency was related to the opening radius, the length, the inside and outside dielectric constant, the permeability of the shirt or cuff. The comprehensive effectiveness of electromagnetic shielding fabrics will be gradually improved if they can meet these regular conditions continually.

Degradation and recovery of In/sub 0.53/Ga/sub 0.47/As photodiodes by 1-MeV fast neutrons

Irradiation damage in In/sub 0.53/Ga/sub 0.47/As p-i-n photodiodes by 1-MeV fast neutrons is studied as a function of fluence for the first time. The degradation of the electrical and optical performance of diodes increases with increasing fluence. The induced lattice defects in the In/sub 0.53/Ga/sub 0.47/As epitaxial layers and the InP substrate are studied by DLTS methods. In the In/sub 0.53/Ga/sub 0.47/As epitaxial layers, hole and electron capture levels are induced by irradiation. The influence of radiation source on device degradation is then discussed by comparison to 1-MeV electrons with respect to the numbers of knock-on atoms and the nonionizing energy loss (NIEL). In order to examine the recovery behavior, isochronal thermal annealing is carried out for temperatures ranging from 75 to 300/spl deg/C. After 300/spl deg/C thermal annealing, the light current only recovers to 20% of pre-irradiation for a fluence of 1/spl times/10/sup 13/ n/cm/sup 2/, while it recovers to 53% for a fluence of 1/spl times/10/sup 15/ e/cm/sup 2/. The different of recovery behavior is thought to be due a different type of radiation damage.

Radiative ignition of double base propellants. II - Pre-ignition events and source effects

In this second paper of a two-part study, emphasis is on the pressure dependent pre-ignition events in double base propellants and the influence of radiation source (arc image vs laser) on observed ignition behavior. The pressure-dependent (< 21 atm) ignition domain of a PNC/MTN double base propellant is examined using controlled exposure lengths together with high speed movies and an infrared detector to monitor flame development. There is a brief flux-dependent period of transient flame development after gasification begins; this is followed by a relatively long, flux-dependent period of steady-state, radiation assisted burning before a selfsustaining condition is reached. The nature of this condition for self-sustainment is not yet well-defined. The ignition behavior seen with an arc furnace or a laser is generally quite close for both double base and composite propellants, if optical effects (reflection, penetration) are factored out. An exception is fast deradiation extinction, seen only with the laser; greater radiation penetration in the arc image wavelength region precludes this phenomenon. I. Introduction A S pointed out in the companion paper,l thermal zmradiation is a convenient energy input for studying solid propellant ignition behavior. By varying such factors as radiant flux, ambient pressure, and propellant compositions, much can be learned about the processes underlying the macroscopic ignition response, e.g., which of these factors controls that behavior in differing ambient conditions and what is needed to predict ignitability quantitatively in new circumstances. At the same time, one must be aware that the unique nature of radiation and the characteristics of the devices used to produce it can affect the test results. The present study is a systematic survey of radiation ignition behavior of a variety of propellants, intended to illustrate both these positive and negative aspects. In the companion paper,1 a generalized ignition behavior 4'map'* (log °f irradiation time vs log of radiant flux) was presented. The boundaries on this map were discerned by go/no-go testing and by monitoring of IR radiation from the developing flame. For clarity, we summarize them again here in the order they are encountered as irradiation time increases: Lla = first gas evolution; Llb = first IR signal from the surface region indicating the beginning of exothermicity; L]c = incipient flame indicated by a roughly 50-fold increase in IR signal; Lld = self -sustained flame indicated by steady burning if flux is removed; L2 = deradiation extinction boundary indicated by disappearance of a well-developed flame when radiation is removed too quickly. The companion paperl concentrated on certain propellant formulation effects; it illustrated how these boundaries are shifted strongly by the optical properties of the propellants. This was shown to obscure the comparison of different types of propellants, but unmodified double base propellants