[en] Constrained molecular dynamics simulations were carried out to investigate the lithium chloride ionic associations in dilute aqueous solutions over a wide temperature range. Solvent mediated potentials of mean force have been carefully calculated at different thermodynamic conditions. Two intermediate states of ionic association can be well identified with an energy barrier from the oscillatory free energy profile. Clear pictures for the microscopic association structures are presented with a remarkable feature of strong hydration effect of lithium ion and the bridging role of its hydrating complex. Experimental association constants have been reasonably reproduced and a general trend of the increasing ionic association at high temperatures and low densities was observed. Additional simulations with different numbers of water molecules have been performed to check the possible artifacts introducing from periodic and finite size effects and confirm the reliability of our simulation results. Marginal differences of the simulated curves are believed to result from the significant compensation and canceling effect between the bare ionic forces and solvent induced mean force. Finally we confirmed the importance of accurate descriptions of dielectric properties of solvent in the ionic association study

[en] In order to characterize the relationship between the hydrodynamic effect and the thermal effect in fragmentation of the molten core structural material with the interaction of sodium, the present study focuses on the fragmentation of a single molten stainless steel (304SS) droplet of 5 g with a high range of ambient Weber number (We_a) from 199 to 586. The fine fragmentation of the single molten stainless steel droplet with high We_a was clearly observed even at the instantaneous contact interface temperatures (T_i) between the droplet and sodium well below its melting point. The fragment size distributions with the high We_a tend to be less than those with the low We_a from 56 to 95 obtained in the previous experiment by the authors under the low T_i condition. As We_a increases, the hydrodynamic effect in fragmentation becomes predominant even under the low T_i condition. Under the high We_a or the high T_i condition separately, the size distributions of the present single metal droplet and the jet reported by Schins' group with 1000-fold difference in mass show almost the same level. The relatively larger size distributions of the single metal droplet only arise under the both low We_a and low T_i conditions. (author)

[en] Safety culture is the cure of the corporate culture for nuclear technology application unit's. This article introduces the definition, connotation and levels of safety culture, and discusses the requirements of safety culture for organization and individuals in the area of technology application. Finally, key practical issues for the cultivation of safety culture are explained and some ideas about the construction of safety culture are proposed. (authors)

[en] In order to characterize the relationship between the hydrodynamic effect and the thermal effect in fragmentation of the molten core structural material with the interaction of sodium, the present study focuses on the fragmentation of a single molten stainless steel droplet of 5 g with a high range of ambient Weber number (We_a) from 226 to 586. The fine fragmentation of the single molten stainless steel droplet with high We_a was clearly observed even at the instantaneous contact interface temperatures (T_i) between the droplet and sodium well below its melting point. The fragment size distributions with the high We_a tend to be less than those with the low We_a from 56 to 95 obtained in the previous experiment by the authors under the low T_i condition. As We_a increases, the hydrodynamic effect in fragmentation becomes predominant even under the low T_i condition. Under the high We_a or the high T_i condition separately, the size distributions of the present single metal droplet and the jet reported by Schins' group with 1000-fold difference in mass show almost the same values. The relatively larger size distributions of the single metal droplet only arise under the both low We_a and low T_i condition. (author)

[en] A compact femtosecond Ti:sapphire/KrF laser system which produces ultraviolet and ultrashort pulse has been developed. It consists of a mode-locked Ti:Sapphire laser, a regenerative amplifier, a frequency conversion system and a KrF excimer amplifier. The system can produce 50 mJ of pulse energy at a pulse width of 440 fs. The pulse width can be reduced down to 100 fs region using a prism pair compressor. (author)

[en] Precise synchronization of an electron bunch and a laser pulse is required to generate an X-ray pulse by 90 deg. inverse Compton scattering. The stability of a mode-locked oscillator is primarily essential for the total laser system. We minimized the pulse timing fluctuation of a mode-locked Ti:sapphire oscillator using a low-noise all-solid-state pumping source to reduce the gain fluctuation and to control the position of a mirror to stabilize the cavity length with an active feedback. The short-term jitter was reduced to 77 fs and the long-term frequency drift was reduced to 70 μHz

[en] The main points and importance of self-evaluation of radiation safety and protection by nuclear technology units are presented. The problems existing in the self-assessment of radiation safety and protection are analyzed, such as establishment and staff role of radiation safety management organization, simple and ambiguous information of operation, as well as inadequate monitoring and analysis. (authors)

[en] Inasmuch as the status of environmental pollution caused by SO₂ is more and more serious and the policy of environmental protection is executed more and more strictly, desulfurization from flue gas (FGD) is introduced to a wide-spread field of national economy. By a comparison with lime-limestone method, the application of adsorption method in FGD is more effective in desulfurization and more adapted to the situation of our country in respect of its more valuable byproduct. However, the technique of adsorption method is limited by the large amount of adsorbent used. In this paper, activated carbon fiber (ACF) is proposed as a new type of adsorbent to apply in FGD. A series of experiments have been made in order to compare the performances between ACF and granular activated carbon (GAC) which has been mostly used. Experiments show that under the same working conditions ACF's adsorption capacity is 16.6 times as high as that of GAC, mass loss rate is 1/12 of GAC's, desorption efficiency of ACF can reach 99.9%. The theory of micropore adsorption dynamics is adopted to analyze the characteristics of both adsorbents. It is indicated that adsorbability and perfectibility of desorption are tightly related to the distribution of pores and the surface micromechanism of adsorbent surface. The accessibility of pores for specified adsorptive and the effects of capillary condensation are crucial factors to influence the process of FGD. According to the research of different adsorbents, conclusion can be drawn that ACF is a kind of good material with a strong selectivity for SO₂. Compared with the traditional methods of FGD, the use of ACF can greatly economize the consumption of adsorbent and obviously reduce the introduction of new adsorbent, and at the same time keep down the equipment investment and operating cost. (authors)

[en] Objective: To study the plasma copeptin levels in patients with some cardiac and pulmonary diseases. Methods: Plasma levels of copeptin were measured with RIA in 21 patients with CHD, 16 patients with asthma, 17 patients with lung cancer and 30 controls. Results: The plasma levels of copeptin were significantly higher in CHD and lung cancer patients (215±14 and 336± 109 vs 54±4pg/ml in controls, P<0.01), but were not significantly different from those in controls in patients with asthma (75±14 vs 54±4pg/ml in controls, P>0.05). Conclusion: The vasopressin system is activated in patients with CHD and lung cancer as indicated by changes in copeptin a peptide derived from vasopressin precursor level. As a potential risk factor for those diseases, plasma copeptin activation might have important prognostic significance. (authors)

[en] The progression of hypothetical core disruptive accidents (CDAs) in metal fuel cores is strongly affected by exclusion of molten metal fuel from the core region due to molten fuel-coolant interaction (FCI). As a basic study of FCI, the present paper focuses on the fragmentation characteristics of continuous molten copper droplets with a total mass from 20 to 50 g penetrating into a sodium pool. The results show that the fragmentation of the continuous molten copper droplets is sensitive to the change of the hydrodynamic and thermal conditions when the instantaneous contact interface temperature (T_i) is lower than the turning point (T_tp) and insensitive at T_i > T_tp. Compared with the fragmentation of a single droplet, the fragmentation of continuous droplets is accelerated and enhanced due to the collision between the droplets and the upward microjets. The present mass median diameter (D_m) or dimensionless mass median diameter (D_m/D₀) of continuous copper droplets shows a distribution with smaller values than those of single copper droplet, and larger values than those of copper jets under similar thermal and hydrodynamic conditions. These results are promising to assure the termination of accidents in CDAs and useful to the core design with enhanced safety in FBRs. (author)