مجله علوم و فناوری های پدافند نوین
پیاپی 1 (پاییز 1389)

Ozone gas is applied in treatment of water contaminated with chemical warfare (CW) agents such as HD and VX. Ozonation has been reported as a suitable process for water decontamination and is able to irreversibly decompose CWs. In this paper decomposition rates of HD and VX during ozonation are reported and decomposition products which were identified using GC-MS, are introduced.

In recent years, wireless technology has experienced a tremendous rise in popularity and usage, opening new fields of applications in the domain of networking. One of such fields concerns Ad Hoc networks in which the mobile nodes do not rely on any predefined network infrastructure. By definition, the nature of Ad Hoc networks is dynamically changing and they have a fully decentralized topology. Hence security is hard to achieve due to the dynamic nature of the participating nodes as well as the vulnerabilities and limitations of the wireless transmission medium. In this paper, an IDS for detection of active attacks against the routing fabric of mobile Ad Hoc networks is proposed. The system is designed to take countermeasures to minimize the effectiveness of an attack and keep the performance of the network within acceptable limits. The novelty of the system lies in the fact that it does not alter the basic routing protocol of the network. The proposed architecture was simulated with OPNET network simulator and numerical results were studied and analyzed.

Fentanyl and its analogues are highly potent and clinically widely used as narcotic analgesics and represent a particular class of ì agonist. These compounds are known as non-lethal chemical warfare agents. A very large number of fentanyl analogues (FA) have been synthesized, with the aim of establishing structure-activity relationship (SAR) and finding clinically more useful drugs with better pharmaceutical profile such as high potency and less side effects (e. g. respiratory depression and lower addiction potential). The most well-known FA are 3-methyl fentanyl, ohmefentanyl, lofentanil, carfentanil, alfentanil and sufentanil. ED50 of different FA are reported but these data are not considered all together to deduce structure-activity relationship. In this contribution, the effect of 5 groups contributing to the analgesic activity of FA (70 compounds) are reinvestigated. The best groups are determined and more effective fentanyl analogue is suggested. We have tried to determine the relative weight of effective groups on ED50 of FA, but comparison of different data indicates that actions of different groups on ED50 are not independent. In another part, atomic electron density and conformational studies of FA by abinitio methods are correlated with their respective ED50.

A new method for noise cancellation of reflected RADAR signal is proposed in this paper. With customary signal processing techniques such as Fourier transform or short time Fourier transform, some signal parameters are extracted. Using Chirplet transform which represent signal in time, frequency, shear, rotation and scale with non-stationary assumption, some signal parameters are estimated. Our presented algorithm is implemented on real RADAR signatures and the result illustrates very good performance in noise cancellation of reflected RADAR signal.

In recent years application of QSAR technique has shown that, there are mathematical relationships between chemical structures and biological activities of compounds. In this method, by changing some specific directions on main molecule composition like, altering electronical shape, shifting in hydrophobicity values of molecule and certain specific changes in general structure of main molecule composition results in creation of a molecule with new chemo-physical properties and biological activities. In this method, by measuring physical and chemical properties of a family of molecules and comparing their biological activities (like: toxicity, drug properties, etc.), a data bank of molecular properties is created. The method of linkage analysis of molecules is used and important physiochemical properties and their correlation with specific biological properties is stored in this data bank.In this way, the method provides possibilities to design a new molecule with certain biological properties. As a conclusion, it has been shown that there are very close dependency between biological activities of phosphoramidate compounds and their respective hydrophobicity.

Increased uses of microwave radiation in communication systems like mobile phones, radars and satellites, have pushed us to do some experimental studies on the biological effects of such radiations. Experiments were performed on cell line of Vero (African green monkey kidney cell), which were exposed to constant power electromagnetic fields with a frequency of about 9 GHz in rest (G1) and growth situations. The cells are exposed to varying field strengths at different times.The cytopathic effects (CPE) and cell proliferation before and after exposure are monitored. Experiments reveals that electromagnetic fields did not affect on cells in rest situation, but arrest the cell cycle transiently in proliferating ones. At prolonged exposure time, damaged cells were not repaired or were destroyed, so more faulty cells were produced. As some molecules like P53, cyclin-D1, PCNA and HSP (Heat shock proteins), probable mechanisms of growth stoppage are discussed.

Microstrip lines and tracks of Printed Circuit Boards (PCBs) have definitive effects on the electromagnetic wave induction and interference on boards. In this paper the effect of changes in the physical characteristics of conductive lines and PCBs was simulated three dimensionally using Finite Difference Time Domain (FDTD) method. The length and width of a microstrip line and thickness of PCB are among parameters that variation effects of which are presented using simulation. High power Electromagnetic radiation effect on a transistor amplifier is also investigated by introducing corresponding electromagnetic equations into the simulation software using BJT GP model