JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2004 | Volume:14 | Issue:51|Papers Count:10

A highly selective electrode for Bromide ion based on azapyrilium derivatives as an excellent ionophore is described .The sensor exhibits a good linear response with a slope of (60+1)mV per decade over the concentration range of (1×10-3- 9×10-6M), and a detection limit of (3×l0-6 M) of Bromide ions .The electrode response is independent of pH in the range of (4.0-9.5). Selectivity coefficients determined by the matched potential method (MPM). Indicate that the interference from inorganic and organic anions is negligible. The proposed sensor shows a fast response time of approximately (20 s). It has been used as an indicator electrode in potentiometric titration of Bromide with Ag+.

Complex formation of calix[n]arene derivatives (n=4,6) with alkalin ion are discoused in equeous solutions and ambient temprature. According to complex formation the concentration of complexed calix [n]arens are increased in aqueous solution. For This manner, the spectrometric method has been used. The stability of formed complexes depend on both substituents on upper rim and size of cavities in Calix arene. The exprimental studies show that the calix[6]arene without any subsituents on upper rim, can obtain the most stable complex.

The following research was carried out to study the antimicrobial activities and, chemical composition of 8 samples of honey collected from various locations of Iran. Most of the samples came from a specific family of plants out of possible 122 various plant soureces. Various chemical experiments including measuring percentage of sucrose, fructose-glucose,- before and after sugar, -ratio of fructose to glucose, percentage of reduction of sugar fructose + glucose, pH, acidity, hydrogen peroxide, catalase, phytest, iodine measurements, before & after sugar, consumption refractometric measurement and Bx Were performed. The measurments were made according to the guidelines of Iranian standard vol. 19. The microbes used in this investigated were Staphylococcus aureus (PTCC 1337), Staphylococcus epidermidis (PTCC 1114), Pseudomonas aeruginosa (pTCC 1074), Candida albicans (PTCC 5027). The Microbial inhibite experiments were carried out using two methods, zone inhibitory and pour plate. In addition the MIC were also measured. The result proved that the climate condition of the area where the honey were produced had no impact on its antimicrobial activity. The honeys produced from different plants exhibited different levels of antimicrobial activities. The honey sample from Loristan province which came from the plants consisting of labiaceae, papionaceae, rosaceae and citrus family had the highest level of anti bacterial activity. The honey from Damavand region which, from a chemical composition point of view was more pure and come from the citrus family of plants, had the second highest level of antibacterial activity. All honey samples except the Khonsar sample, exhibited antibacterial activity towards the Pseudomonas bacteria.The Staphylococcus aureas did exhibit resistance against the Khansar and Firoozkooh honey samples. The epidermidis did exhibit resistance against the Khansar, & Jahrom & Firoozkooh samples. None of the samples used in the experiments showed any antifungal’s activity towards the Candida albicans funges. We showed mention that the level of anti bacterial activity mainly depends on the source of plants of the honey made of and its chemical composition and properties including acidity, osmolarity and hydrogen peroxide of each honey sample.

With respect of ABA effect on different plant growth condition, probability there is a relation between internal factor and resistance for environmental stresses, which in this result have been studied. In this experiment 3 different hormonal concentration at 0, 20 and 40 PPM with 3 different water potential at 0, -4, and -8 Bar at different temperature (15, 25, and 35°c) on five different pasture species (Agropyon thrichophorom, Bromus tomentellus, Festuca ovina, Secal montanum, Stipa barbata) were examined.The experiment were conducted in Split Plat in place with 135 variables. The result showed that at hormonal activity with decrease of water potential and increase of temperature, rate of Proline Amino Acid and internal ABA were increased. Also result show the there is a kind of adaptability of plant to environmental stress for growth and developmental activity

Sedimentologhy studies of Karaj alluvial fan caused the climate were surveyed in the time of sedimentation of alluvium of a,b,c in plio - plioctocen. Existence of pyroxene and plagioclase with rounded quartz (with different properties and degradation level) in alluvium of a and c indicate ancient sedimentary cycles, fast transportation and sedimentation. Observation of unanalyzed pyroxene and plagioclase indicate moisture conditions in source but fast transportation and sedimentation have prevented for continuing.The percentage of chlorite is more than the other clay minerals and also observation of pyroxene in alluvium of a,b,c indicate the lack of wet conditions in Karaj sedimentary basin. Considering the lack of moisture in Karaj sedimentary basin, the source of mixed - layers of clay minerals can lit be neoformation and transformation .so they have inheritage origin.Considering the kind of minerals in alluvium of a,b,c and the color of sediments , the climate was cold and dry with short period of warm and dry in Karaj sedimentary basin in plio – plioctocen. Existence of debris flow in alluvium of a,b,c and inheritance sources of clay minerals indicate wet conditions so the climate of Karaj Water -shed was cold and wet in plioplioctocen.

Thin films of CaF2 were prepared and used as the insulator material in MIM structures, where the metal M was Al and Cu. Devices with Cu electrodes were readily formed by application of forming voltage, while devices with Al electrodes were not formed even by application of 50 volts up to 20 hours. For devices formed with Cu electrodes the peak circulating current was observed at a voltage of the order of 3.5-4.5 volts. At this applied voltage the electron emission current rose sharply and reached values comparable with those measured from other MIM structures.Current - Voltage characteristics of devices carrying Al electrodes were montonically increasing and believed to be obeying Poole - Frenkel effect. The polyfilamentary model was used to explain the observed electroforming process in M/CaF2/M structures.

A neutron source in the epithermal energy range for use in medical treatment employing Boron Neutron capture therapy (BNCT) technique is designed. Neutronic MCNP code is used in this design. Calculation for the design of target is performed for choosing type of target, filters, geometry and also the kind of reflector and shielding. Target is the first layer that proton beam undergoes interaction with. The neutron producing reaction is 7Li(p,n)7Be.Calculation for pure Li and also for LiF as target have been performed. The result of calculation showed that suitable thickness of Li or LiF is in the range of 0.1 to 0.5 Cm. Some kind of Fluorine compound is used for lowering neutron energy to energy suitable for treatment (i.e.24 KeV). The result of analysis showed that a 10 Cm thick lead fluoride is the most suitable Fluorine compound .Due to the neutron scattering cross section resonance at 24 KeV, neutron energy is reduced to around 24 KeV after leaving Iron filter. Lead is superior, because of its high atomic concentration and availability, as a reflector material used for increasing neutron flux in treatment port. We achieved a better neutron source design in the following aspects:1- Using LiF instead of Li because it is easier for target preparation and for its long time storage without appreciable changes in structure or chemical composition .The existing fluorine in target also contributes to reduce of neutrons energy, which is desirable for this application.2- Increasing neutrons flux in treatment range.

Direct laser driven inertial confinement fusion showed numerous anomalies in the laser interacjion process including parametric instabilities, self-focusing (filamentation) and the later confirmed stochastic pulsation in the 10 ps range. Smoothing of the laser beam resulted in a dramatic reduction of parametric processes and filamentation, and a strong increase of direct driven laser-fusion gains without that a convincing explanation was given before. An explanation for the effects of by laser beam smoothing is based here on some calculations for the suppression of the stochastic pulsation intermixed with mechanism of instabilities by frequency modulated laser pulses. The stochastic pulsation of the interaction in the 10 ps range could be analyzed numerically as due to changes between mirror reflection and phase reflection caused by self generated von - laue diffraction by nonlinear force produced density rippling in the plasma and its thermo-kinetic decay. Solving this problem by broad band laser beam smoothing was shown numerically and is applied to the measured suppression of pulsation by random phase plates. One of the key experiments hidden in the broad steam of publications is the question mark experiment of Pant et al. As a tool for testing the degree of elimination of the anomalies. This may permit direct drive low cost laser fusion using three times more energetic laser beams without expensive harmonics generation and its problems in the next facilities of NIF scale.

In this paper we use a simple but very important modification of proposed model by Saati et al. for classification and determining stability radius and variations ranges of efficient and inefficient Decision Making Units (DMUs). In the suggested method, the number of problems which are solved, is less than of previous methods. Furthermore, relying on work of Jahanshahloo et al. that was presented for ranking DMUs. in this paper we use it to determinate ranges within which all data may be varied for any DMUs before a reclassification from efficient to inefficient status (or vise versa) occurs. We apply the presented method for real world data set.