[en] Seaweed sulfated polysaccharide (SP) is a natural sulfated polysaccharide isolated from seaweed and has various pharmacological activities. However, previous studies on the radioprotective effect of SP were limited to in vivo whole-body studies. In the present study, SP was examined for radioprotective effect and its mechanism by MTT assay and the electron spin resonance (ESR). The items studied were as follows: (1) Different doses of SP were given to ⁶⁰Co γ-ray irradiated KM mice, and their influence on the peripheral blood recovery and 30 d survival rate of the irradiated mice were observed. (2) The radioprotective mechanism of SP on hematopoietic cells was studied in two hematopoietic growth factor-dependent cell lines (NFS-60 to G-CSF, TF-1 to GM-CSF) by MTT assay. (3) The irradiated 5'-TMP was used as a model for estimating the amount of DNA to observe the protective activity of SP on the radiation injury of DNA by using ESR. The results found that SP could promote the recovery of peripheral blood and proliferation of the hematopoietic cells in irradiated mice, increase their 30 d survival rate, and scavenge the free radicals

[en] The seismic response analysis and test of CHASNUPP steam generator lower part model has been performed. The lower part model consists of a tube sheet, 441 U-shaped rods (modeled on U-shaped tubes), 9 tie rods, a tube bundle wrapper, a lower shell and some position bolts between the lower shell and the wrapper. The analytical and experimental data show that the steam generator lower part model is more stiffer than pure tube bundle model. The movement of the lower part model appears in a systematic model in earthquake condition. The fundamental natural frequency of this model is higher than that of the tube bundle model and lower than that of the lower shell. The global frequency components are absolutely dominant and the local frequency components are insignificant. The experimental data are in good agreement with the results from finite element method. The effectiveness of mathematical model is verified

[en] The screening wheat new lines which have the resistance to Fusarium graminearum were completed by in vitro induced mutation and cell screening. Four new lines with resistance to Fusarium graminearum were obtained. The field inoculating determination in 1990∼1996 showed that their resistance was 1∼2 degree higher than that of parents, and there were variations in main agronomic traits between the new lines and their parents. Changes of the defensive enzymes (SOD, POD), sugar-protein on cell surface, and ultrastructure were investigated by using new lines and their parents under the action of toxin of Fusarium graminearum. The new lines under the action of toxin of Fusarium graminearum have the ability to increase the defensive enzyme activity and thickness of sugarprotein on cell surface and to reduce the damage of cell membrane system that would result in resistance increasing. (8 refs., 3 figs., 3 tabs.)

[en] The equations for finding lattice constants of the 7 crystal systems were completely deduced using the M.U.Cohen least square method. From the deduction process it is obvious that the equation forms had nothing to do with the extrapolation functions so any of them can be used. (But in practice, cos²θ and cos²θ(1/sinθ + 1/θ) were generally performed.) After a personal computer program was finished using above mathematic model, the lattice constants of materials for storage of hydrogen ZrCo and LaNi_5-xM_x (M = Mn, Al) were determined. The results showed that the program is very good for finding lattice parameters and can be used in the 7 crystal systems. The results also showed to the LaNi₅ alloy its lattice constants increase when the elements (such as Mn, Al, etc.) whose atomic radii are larger than that of Ni are substituted for Ni and when the content of the same substitutional element Al goes up. This phenomenon is in accordance with the theory

[en] The model of environmental dispersion of gaseous effluence under normal operation from a nuclear power plant with 600 MWe is established to give a mathematical expression of annual mean atmospheric dispersion factor under mixing release condition based on quality assessment of radiological environment for 30 years of Chinese nuclear industry. In calculation, the impact from calm and other following factors have been taken into account: mixing layer, dry and wet deposition, radioactive decay and buildings. The doses caused from the following exposure pathways are also given by this model: external exposure from immersion cloud and ground deposition, internal exposure due to inhalation and ingestion. The code is named as ROULEA. It contains four modules, i.e. INPUT, ANRTRI, CHIQV and DOSE for calculating 4-dimension joint frequency, annual mean atmospheric dispersion factor and doses

[en] According to the theory of particle transport and dynamics of molecular gas, the mathematic model of three-dimensional transient numerical simulation of indoor radon transport has been setup, and the different boundary condition has been offered. By means of the different method, the equations of transport of indoor radon gas, convection velocity and pressure difference and boundary conditions have been discretized. After programming and calculating, the numerical simulation has been finished. Comparing with references and experiments, the indoor radon concentrations of simulation are in good agreement with them. Meanwhile, the real changing processes of the radon in indoor and cracks have been simulated, when the environmental factors (such as atmosphere, temperature, wind and mechanic air-conditioning) changed with time. The calculating results show that the radon concentrations in indoor and cracks are affected, when the indoor pressure difference are induced by the environmental factors; comparing with the steady results, the phase difference between the indoor radon and pressure difference is bigger than 180 degree; and the indoor radon concentration is much obviously affected by the radon in cracks

[en] It is pointed out that the main reason making nuclear power plants reactors leak is the vibration of internals of reactors. The factors which lead the vibration all have randomness and obscureness. The obscure reliability theory is introduced to the vibration system of internals of nuclear power reactor. Based on a quantity of designing and moving data, the obscure factors effecting the vibration reliability of the internals of nuclear power plant reactor are analyzed and the anti-vibration reliability criteria and the evaluating model are given. And the anti-vibration reliability measures are advanced from different quarters of the machine design and building, the thermohydraulics design, the control of reactivity, etc.. They may benefit the theory and practice for building and perfecting the vibration obscure reliability model of the reactor internals

[en] The modeling and simulation of nuclear power plant control system has been investigated. Some mathematical models for rapid and accurate simulation are derived, including core models, pressurizer model, steam generator model, etc. Several numerical methods such as Runge-Kutta Method and Treanor Method are adopted to solve the above system models. In order to model the control system conveniently, a block diagram-oriented visual modeling platform is designed. And the Discrete Similarity Method is used to calculate the control system models. A corresponding simulating software, NCS, is developed for researching on the control systems of commercial nuclear power plant. And some satisfactory results are obtained. The research works will be of referential and applying value to design and analysis of nuclear power plant control system

[en] The recent advances Concerning high-order harmonic generation results obtained with different laser systems in strong laser-fields are reviewed. The influence of the laser pulse width, the excitation wavelength (from the near infrared to the ultraviolet) and the atomic systems on the number of photons produced and on the maximum energy attained are investigated. Harmonic generation also depends strongly on the focusing conditions. Based on the experimental results from different references, a discussion is made on the characteristic harmonic distribution including a broad plateau, the role of ac stark effects in the plateau formation, the fundamental-wavelength dependence of harmonic generation

[en] As a new material, the study on the metallograph and properties of Ta-12W alloy has been set about to testify its employ characteristics. The alloy's metallograph specimen preparation methods to illustrate microstructure are found out, 12 dose of chemical-corrosives are given. The author studies the metallograph, weld structure and properties, and chemical-corrosive resistance, provides scientific base for future research on Ta-12 W alloy