Hung Van Nguyen’s scientific contributions

Neutron activation analysis using nuclear reactor has been used widely to determine of content of elements in environment, biology, geology, archaeology, etc. In this report, determination of content of some elements in the human blood by method of instrumental neutron activation analysis using Dalat nuclear reactor coupled with processing of results by k-zero method (using k0-Dalat code) and by relative one (using standard samples) is presented. 50 samples of the human blood are mainly collected from public objects in Lamdong province. They are prepared and activated together with the standard samples at the dry channel No. 7-1 and the rotary specimen rack (wet channel) of the reactor. Then they are directly measured by the HPGe gamma spectrometer and the measured data are processed. The experimental results for determination of ranges of contents and average values for 8 elements respectively are Na (1.06 - 2,48; 1.71 ± 0.30 mg/ml), Cl (1.10 - 3.75; 2.66 ± 0.71 mg/ml), Fe (0.26 - 0.72; 0.49 ± 0.09 mg/ml), K (0.31 - 1.14; 0.73 ± 0.15 mg/ml), Zn (4.55 - 13.97; 8.08 ± 1.24 μg/ml), Rb (2.73 - 7.92; 5.11 ± 0.86 μg/ml), Se (0.04 - 0.18; 0.08 ± 0.03 μg/ml) and Sc (0.22 – 1.61; 0.56 ± 0.24 ng/ml). Besides, content of sodium to be determined by the k-zero method and the relative one are compared also. The results for determination of contents of 8 elements in the human samples to be compared with those of other authers are shown that this method has had confidence, and it could be applied routinely in determination of contents of multi-elements.

At present, thickness measurement of materials based on effect of backscattering gamma has been used widely in industry in our country. This report presents research in thickness of some materials such as paper, plastic, aluminum and steel using the specialized system of MYO-101 (with using scintillation detector of YAP(Ce) and gamma-ray of 60 keV of source of Am-241) by Monte-Carlo simulation with using the code of MCNP, and the simulation was checked by experimental measurements. The results show that the experiment and the simulation are in agreement in the error limit. This research can be useful for training activities in the field of application of nuclear technique in industry in Vietnam.

In 1940, two cultivation methods for siliceous marine algae were developted in Japan. Fujinaga determined that Skeletonema costatum and Chaetoceros sp. Algae originally were the main food of larval shrimps from the phase of Zoea until the phase of Postlavae. In Viet Nam, by early 1970's, the cultivation of high value aquatic products started to atract attention. In this context, many researchs have been focus on algae cultivation in order to find the suitable species for local condition. In this study, Chaetoceros calcitrans algae were massed on TT3 medium with cell density of 20.104 cell.ml-1, 40.104cell.ml-1, 60.104 cell.ml-1, 80.104 cell.ml-1. The optimal cell density was 60.104 cell.ml-1. Chaetoceros calcitrans algae was cultured on Liao medium, TT3 medium, ƒ2 medium. Using Chaetoceros calcitrans algae as supplemental fresh food for white shrims larval from the phase of Nauplius to the phase of 3 Mysis improved the larvae quality and increased the survial rate of larvae from 42 percentage to 76 percentage.