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Luan L.Q.,Center for Nuclear Techniques | Ha V.T.T.,Saigon Thuy Canh Corporation | Uyen N.H.P.,Center for Nuclear Techniques | Trang L.T.T.,Center for Nuclear Techniques | Hien N.Q.,Research and Development Center for Radiation Technology
Journal of Agricultural and Food Chemistry | Year: 2012

Degraded alginate compounds with molecular weights of 7-26, 40-77, or 11-26 kDa were obtained by γ irradiation, hydrogen peroxide (5% H 2O 2) treatment, or a combination treatment involving ionizing radiation and H 2O 2, respectively. The 14 kDa oligoalginate, prepared by the combined method, promoted the growth of mustard greens and lettuce at an optimal concentration of 75 mg/L. The growth promotion effects of the oligoalginate prepared by γ irradiation in the presence of H 2O 2were statistically equivalent to those of the oligoalginate prepared by γ irradiation only. The combination of γ irradiation and H 2O 2reduced the required irradiation dosage by a factor of 9 relative to the oligoalginate produced by γ irradiation only. The combination treatment (γ irradiation/H 2O 2) may be carried out on a large scale at low cost to produce oligoalginate for use as a plant growth promoter in agricultural industries. © 2012 American Chemical Society. Source


Van Hung T.,Research and Development Center for Radiation Technology
Kerntechnik | Year: 2013

Age-dependent effective dose for external exposure to photons uniformly distributed in air were calculated. Firstly, organ doses were calculated with a series of age-specific MIRD-5 type phantoms using the Monte Carlo code MCNP. The calculations were performed for mono-energetic photon sources with source energies from 10 keV to J MeV and for phantoms of newborn, 1, 5, 10, and 15 years-old and adult. Then, the effective doses to the different age-phantoms from the mono-energetic photon sources were estimated based on the obtained organ doses. From the calculated results, it is shown that the effective doses depend on the body size; the effective doses in younger phantoms are higher than those in the older phantoms, especially below 100 keV. © Carl Hanser Verlag, München. Source


Van Hung T.,Research and Development Center for Radiation Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

A modified method has been developed for the α determination in the 1/E 1+α epithermal neutron spectrum of reactor. It is based on the Cd-covered and without Cd-covered irradiations of two monitors. This method was applied to determine the α value in the channels of Dalat reactor and the results were compared with those obtained by the other methods. It appeared that the results of the modified method were in quite good agreement with those of other methods. It also showed that the modified method was simple in practical uses and a good application in the experiment of α determination in the reactor irradiation channels. © 2010 Akadémiai Kiadó, Budapest, Hungary. Source


Van Hung T.,Research and Development Center for Radiation Technology
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

The α-factor is a measure of the epithermal neutron flux deviation from the ideal distribution 1/E, where E is neutron energy. It defends on the position of the irradiation channel in reactor. A determination method of the α-factors in irradiation channels of Dalat reactor is presented by fitting the epithermal neutron spectrum obtained from the calculation using MCNP code. The fitting α-values were compared to those by experiment used the "Cd-ratio" method with monitors 197Au-94Zr and 197Au-64Zn. It shows that the α-values calculated from neutron spectra agree well with experimental ones. The difference between both data is about 6%. © 2010 Akadémiai Kiadó, Budapest, Hungary. Source


van Phu D.,Research and Development Center for Radiation Technology | Lang V.T.K.,Research and Development Center for Radiation Technology | Lan N.T.K.,Research and Development Center for Radiation Technology | Duy N.N.,Research and Development Center for Radiation Technology | And 4 more authors.
Journal of Experimental Nanoscience | Year: 2010

Radiation-induced synthesis of colloidal silver nanoparticles (Ag-NPs) using chitosan (CTS) as a stabiliser and free radical scavenger is feasible and satisfiable to green method. The conversion dose (Ag+ into Ag0) was determined by UV-Vis spectroscopy and Ag-NPs size was characterised by transmission electron microscopy. The average diameter of Ag-NPs was smaller than 10nm with narrow size distribution and the colloidal Ag-NPs have good stability for a long time of storage. The effect of several parameters, such as pH, Ag+ and CTS concentration and molecular weight of CTS on Ag-NPs size was also investigated. Ag-NPs of 7nm exhibited highly antimicrobial effect. The inhibitory efficiency of Ag-NPs for Staphylococcus aureus was more than 99.9% at 5 ppm and the effective dose (ED50) of inhibition for Corticium salmonicolor was of 27.2ppm. © 2010 Taylor & Francis. Source

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