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[en] Sorption of U(Ⅵ) on goethite has been studied as a function of time conditions: amount of goethite 5 g/L, U(Ⅵ) concentration: 3 × 10"-"6-4 × 10"-"4 mol/L, ionic strength: 0.001-0.5 mol/L NaCl 0.1-0.5 mol/L NaNO_3, pH 2.5-10. The sorption isotherms of U(Ⅵ) were determined at approximately constant pH (3.75 ± 0.03) and different ionic strengths. It was found that the best experimental condition: 5 g/L, 48 h. The sorption and the desorption experimental points at constant pH (3.75) are almost in the same line. (authors)
[en] To understand the migration mechanisms of phosphorus (P) during coal-based reduction, a high-phosphorus oolitic iron ore was reduced by coal under various experimental conditions. The migration characteristics and kinetics of P were investigated by a field-emission electron probe microanalyzer (FE-EPMA) and using the basic principle of solid phase mass transfer, respectively. Experimental results showed that the P transferred from the slag to the metallic phase during reduction, and the migration process could be divided into three stages: phosphorus diffusing from the slag to the metallic interface, the formation of Fe-P compounds at the slag-metal interface and P diffusing from the slag-metal interface to the metallic interior. The reduction time and temperature significantly influenced the phosphorus content of the metallic and slag phases. The P content of the metallic phase increased with increasing reduction time and temperature, while that of the slag phase gradually decreased. The P diffusion constant and activation energy were determined and a migration kinetics model of P in coal-based reduction was proposed. P diffusion in the metallic phase was the controlling step of the P migration.
[en] The beam optical transfer is important for neutron generator research, therefore the research of the beam transfer system was conducted and the system optical character and composition were expatiated. As a typical case, the composition and optical characteristics of the transfer system of ns-200 neutron generator were detailedly analyzed. The data input card of this system was derived according to LEADS software requirement. The simulation calculation produces the beam transfer envelope using relevant optical calculation modules of LEADS based on the card. The envelope agrees well with the designed one. (authors)
[en] During the first outage of unit2 of LINGAO nuclear power plant, the excursion of the precision of analogue acquisition module from steam generator's feed water flow measurement channel was founded in the system examine test, the design precision of this acquisition module is 0.02%, however, the maximal precision which was founded in the system examine test was 0.074%. In order to evaluate the variety of reactor thermal power uncertainty calculation result because of the precision excursion of analogue acquisition module, using uncertainty calculation theoretic to calculate the reactor thermal power's total uncertainty that the precision of analogue acquisition module reach to 0.074%. The calculation process is as following: First step: the calculation of β. Second step: the uncertainty calculation of feed water flow. Third step: the correction of feed water flow uncertainty calculation. Fourth step: the enthalpy uncertainty calculation. Fifth step: the reactor thermal power's total uncertainty calculation. The conclusion of five steps calculation is: the total uncertainty of reactor thermal power is not changed at the 100% full power condition. (author)
[en] Supercapacitors based on nanocomposites of manganese oxide (MnO_2) with cationic surfactant of cetyltrimethylammonium bromide (CTAB) or cetyltrimethylammonium chloride (CTAC) are prepared by direct electrodeposition. The obtained nanocomposites of MnO_2: CTAB or MnO_2: CTAC are compared by surface morphologies, specific capacitances and cycling stabilities. The scanning electron microscopy (SEM) images show that MnO_2: CTAC is composed of nano sheets, while MnO_2: CTAB changes morphology from the mixture of nano sheets and nanoparticles to big blocks when CTAB concentration increases. The Brunauer Emmett and Teller (BET) specific area of MnO_2: CTAC is larger than that of MnO_2: CTAB prepared at the same surfactant concentration. Maximal BET specific areas are obtained at concentration of 50 mM for both surfactants. From transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) images, both of the nanocomposites of MnO_2: CTAC and MnO_2: CTAB show polycrystalline laminar structures in nanoscale. The Raman spectrum indicates that birnessite structure of MnO_2 is obtained for both nanocomposites. The maximum of specific capacitance of MnO_2: CTAC is calculated to be 347 F/g, 3 times larger than that of MnO_2: CTAB. The chemical redox reaction of Mn"2"+ with Br_2 molecules from Br"− anion electrooxidation leads to low surface area and small specific capacitance of MnO_2: CTAB. Due to protection by the alkyl chains of surfactants coating on surface of MnO_2, the retention of capacitance after 1500 charge/discharge cycles by MnO_2: CTAC is 90%, which is better than those by pristine MnO_2 (60%) and MnO_2:CTAB (80%). The electrochemical impedance spectroscopy (EIS) shows that the charge transfer resistance of MnO_2: CTAC and MnO_2: CTAB films are slightly larger than that of pristine MnO_2. The dependence of specific capacitance and frequency reveals that MnO_2: CTAC can provide more effective mass for pseudocapacitive reactions
[en] Supercapacitors based on MnO2/CB/C nanocomposites films are prepared by direct electrophoretic deposition (EPD) process on nickel plates in an aqueous solution containing of MnO2 nanoparticles, carbon black (CB) and sodium alginate (SA), followed by carbonization of SA to carbon layer. The nanocomposites of MnO2/CB/C films are prepared from different electrolytic solutions with mass ratios of MnO2 nanoparticles, CB and SA from 8: 1: 1 to 6: 2: 2. Same mass ratios of nanocomposites are prepared by traditional Doctoral Blade (DB) process for morphologies and performances comparisons, in which mixtures of MnO2 nanoparticles, carbon black with polyvinylidene fluoride (PVDF) are used. From scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) images, the MnO2/CB/C shows a uniform aggregation of MnO2 and carbon nanoparticles covered with carbon layers. In the case of the MnO2/CB/PVDF from DB process, the MnO2 nanoparticles are separately clustered, and the clusters are adhered to CB together with PVDF. More uniform film and better contact of MnO2 with CB by carbon layer can be obtained from EPD/Carbonization process. The electrochemical performances of MnO2/CB/C and MnO2/CB/PVDF nanocomposites in different mass ratios are compared by areal specific capacitances (Ca), charge transfer resistance of films and retention of capacitance after 1500 cycles of charge/discharge to test stability respectively. The nanocomposites of MnO2/CB/C show better areal specific capacitances and smaller charge transfer resistances at each ratio. The carbon layer coating on surface of MnO2 nanoparticles can effectively delay the capacitance loss, which leads to 98% of capacitance after charge/discharge cycles, much better than retention of those from DB process (50%). The EPD/Carbonization is an easy way to make carbon layer on pseudo capacitive materials from sodium alginates, and the carbon layer can effectively improve the charge/discharge stability of supercapacitors.
[en] Highlights: •Propose a migration based on strategy and cost in the Prisoner’s Dilemma Game. •The level of cooperation without mutation is higher than that with mutation. •Increased costs have no effect on the level of cooperation without mutation. •The level of cooperation decreases with the increase in cost with mutation. •An optimal density value ρ resulting in the maximum level of cooperation exists. -- Abstract: Humans consider not only their own ability but also the environment around them during the process of migration. Based on this fact, we introduce migration based on strategy and cost into the Spatial Prisoner’s Dilemma Game on a two-dimensional grid. The migration means that agents cannot move when all of the neighbors are cooperators; otherwise, agents move with a probability related to payoff and cost. The result obtained by the computer simulation shows that the moving mechanism based on strategy and cost improves the level of cooperation in a wide parameter space. This occurs because movement based on strategy effectively keeps the cooperative clusters and because movement based on cost effectively regulates the rate of movement. Both types of movement provide a favorable guarantee for the evolution of stable cooperation under the mutation rate q = 0.0. In addition, we discuss the effectiveness of the migration mechanism in the evolution of cooperation under the mutation rate q = 0.001. The result indicates that a higher level of cooperation is obtained at a lower migration cost, whereas cooperation is suppressed at a higher migration cost. Our work may provide an effective method for understanding the emergence of cooperation in our society
[en] The effect of diagonal disorder on superconductivity of the triplet bipolaronic system with a two-delta random site energy distribution is analyzed in the framework of the mean-field approximation. It is found that this kind of disorder strongly affects superconductivity of the system. When the triplet bipolaron concentration is near 1/2, the transition temperature decreased seriously, while when the concentration is small, the normal random site energy cannot impede the occurrence of superconductivity completely. This results from the tunneling motion of triplet bipolarons. It is therefore expected that superconductivity may appear in some amorphous semiconductors with low bipolaron concentration
[en] The problem of coexistence of superconductivity and ferromagnetism in the triplet bipolaronic system has been studied by using the symmetry-breaking Hartree approximation. It is found that the ground state of the system is the mixed state of both orders, which is different from the case of usual BCS systems. It is seen from the phase diagram obtained that in the high bipolaronic concentration region the system may exhibit a transition from the ferromagnetic to the mixed state on cooling, while in the low concentration region only the transition from the normal to the mixed state is possible. When the system is already superconductive, a phase transition to the ferromagnetic state cannot take place