[en] A small-scale circular tube was modeled with the CFD software ANSYS CFX to study the impact of roughness on the resistance characteristics. The calculated pressure drop was compared with the experimental data. By comparison, it was found that the calculated pressure drop was in accordance with the experimental data. Also it was in agreement with the pressure drop that arrived based on the Moody figure. But it had a large difference with the results calculated by the Blasius equation. At last, it was concluded that the roughness had an important impact on the pressure drop characteristics for the small flow path in reactor, such as fuel assembly, heat transfer tube of steam generator and so on. So the roughness must be take into account when make a numerical simulation of a small-scale pipe. But for the engineering pipe, the roughness effect can be ignored. (authors)

[en] The Miniature Neutron Source Reactor (MNSR) is a pool-tank reactor, which adopts natural circulation cooling method and relies on negative feedback to maintain self-stabilization. In this paper, the transient characteristics of reactivity insertion accidents of MNSR with low enrichment uranium (LEU) core are investigated by using a system analysis program named RELAP5/MOD4. Firstly, the stable operation characteristics of MNSR at rated power are established and compared with the existing results, which verifies the accuracy of the calculation model. Then the transient characteristics of reactivity insertion accidents (3.0 mk, 4.5 mk, 6.0 mk) of MNSR at thermal zero power are analyzed, the change of the coolant flow rate, the average coolant temperature in the inlet and outlet of the reactor core, the maximum temperature on the surfaces of fuel elements are mainly obtained. The results show that the good self-stabilization characteristics and inherent safety have been proved in the lower reactivity; when the reactivity is higher, local nucleate boiling on the surfaces of fuel elements will occur. (authors)

[en] Boron nitride (BN) nanometer thin films are synthesized on Si (1 0 0) substrates by RF reactive magnetron sputtering. Then the film surfaces are treated in the case of the base pressure below 5 x 10^-4 Pa and the temperature of 800 and 1000 deg. C, respectively. And the films are studied by Fourier transform infrared spectra (FTIR), atomic force microscopic (AFM) and field emission characteristics at different annealing temperature. The results show that the surface heat treatment makes no apparent influence on the surface morphology of the BN films. The transformations of the sample emission characteristics have to do with the surface negative electron affinity (NEA) of the films possibly. The threshold electric fields are lower for BN samples without heat-treating than the treated films, which possibly ascribed to the surface negative electron affinity effect. A threshold field of 8 V/μm and the emission current of 80 μA are obtained. The surface NEA is still presence at the heat treatment temperature of 800 deg. C and disappeared at temperature of 1000 deg. C

[en] In this study, the passive residual heat removal heat exchanger of AP1000 was used as the prototype. A heat transfer experiment of passive residual heat removal heat exchanger with three C-type tubes was carried out. And then subcooled test conditions were numerically simulated by CFD software. Through numerical calculation, the correlations for calculating the heat transfer of the outside of the tube were obtained. The calculated results using the adopted heat transfer model were in good agreement with the experimental data. With the heat transfer model, the design condition of AP1000 was also verified. It shows that the heat exchanger of AP1000 can remove the core residual heat. Therefore, the model is properly conservative and it can provide a technical support for design and safety analysis of large advanced pressurized water reactor. (authors)

[en] Taking the steam generator (SG) of the ACME facility as the study object, two-fluid model was chosen for the secondary side of the SG and a direct simulation was made on the whole SG of the ACME facility with the CFD software CFX. The stable test conditions were calculated. The primary side and secondary side temperature distribution of SG, the secondary side void fraction distribution and the wall temperature of heat transfer tube were obtained. The secondary side detailed flow and heat transfer characteristics were arrived. The results show that bubbles begin to accumulate from the second baffle and bubble amount increases as the tube is higher. Near the bend area and above, they all become steam. The calculated results are all in accordance with the experimental results. (authors)

[en] Highlights: • An MFC was successfully started up using nitrite as cathodic electron acceptor. • The optimal HRT was deemed to be 8 h in this study. • The suitable temperature for power generation was found to be 20 °C. • The suitable temperature for pollutant removal was found to be 25 °C. • Free buffer led to 50% decrease of TN removal rate and power generation. - Abstract: The influences of hydraulic retention time, temperature and free buffer on the performance of short-cut denitrifying microbial fuel cell were investigated after it was successfully started up using nitrite as the cathodic electron acceptor. The results revealed that a power density of 8.3 ± 0.5 W m⁻³ NC was obtained after 15 days operation. The desirable hydraulic retention time was found in this study to be 8 h, with a COD removal rate of 2.117 ± 0.006 kg m⁻³ NC d⁻¹ and a total nitrogen removal rate of 0.041 ± 0.002 kg m⁻³ NC d⁻¹, respectively. It demonstrated that temperature had different effects on the electricity generation and pollutant removal performance of microbial fuel cell. The suitable temperature for power generation and pollutant removal was found to be 20 °C and 25 °C, respectively. Free buffer led to 50% decrease of both total nitrogen removal rate and power density of microbial fuel cell compared to that with phosphate buffer solution addition. The optimal total nitrogen removal rate obtained in the case with sodium azide addition (0.075 ± 0.008 kg m⁻³ NC d⁻¹) increased by 50% as compared to that without sodium azide addition. It suggested that abolishing oxygen or inhibiting nitrite oxidizing bacteria would favor nitrogen removal

[en] HIGHLIGHT• A mitochondrial viscosity response NIR fluorescence probe DICB was synthesized. • Large Stokes shift of 214–253 nm, selectivity, sensitivity, stability. • Monitoring the mitochondrial viscosity of mitophagy dynamically. • Accurate determination mitochondrial viscosity of inflamed tissues in vivo. Mitochondria are cellular energy factory, having an essential role in cellular metabolism. Furthermore, abnormal changes in mitochondrial viscosity have been confirmed to be closely related to many diseases. Therefore, the development of probe that responsive to mitochondrial viscosity and its application in mitochondrial viscosity measurement is considered to be a new tool for understanding diseases. In this paper, a mitochondrial viscosity probe (DICB) with a large Stokes shift (214–253 nm) was designed and synthesized by modifying the structure of the carbazole fluorophore. The probe DICB has a favorable responsive to viscosity in the near-infrared (NIR) region (703 nm). In the water-glycerol system (0.893 cP −945 cP), the fluorescence intensity of DICB at 703 nm has a 74 times increase; in the range of 5.041 cP-856.0 cp, it has a well linear fitting relationship. Meantime, the probe has excellent sensitivity to viscosity. The probe (DICB) has been confirmed to be able to detect changes of mitochondrial viscosity in cell models induced by nystatin, carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and lipopolysaccharide (LPS); it has also been validated that DICB can be used in the process of autophagy to monitor mitochondrial viscosity. More importantly, DICB can be applied to the detection of abnormal mitochondrial viscosity in inflammatory tissues at the biological level. The outstanding characteristics of DICB for mitochondrial viscosity detection are not only of great importance to the development of viscosity probes, but also provides a universal strategy to study the relationship between inflammatory and mitochondrial viscosity.

[en] Highlights: ► The Thevenin model is improved and a genetic algorithm is used to find the optimal model parameters. ► Three commonly used peak power estimation methods for lithium–ion batteries are compared. ► An online peak power estimation algorithm with multi-parameter constraints is proposed. ► The four peak power estimation methods are evaluated and compared based on a dynamic driving cycle. -- Abstract: A model-based dynamic multi-parameter method for peak power estimation is proposed for batteries and battery management systems (BMSs) used in hybrid electric vehicles (HEVs). The available power must be accurately calculated in order to not damage the battery by over charging or over discharging or by exceeding the designed current or power limit. A model-based dynamic multi-parameter method for peak power estimation of lithium–ion batteries is proposed to calculate the reliable available power in real time, and the design limits such as cell voltage, cell current, cell SoC, cell power are all used as its constraints; more importantly, the relaxation effect also is considered. Where, to improve the model’s accuracy, the ohmic resistance of Thevenin model for the lithium–ion battery has been refined; in order to further improve the polarization parameters identification precision, a genetic algorithm has been used to gain the optimal time constant. Lastly, a test with several consecutive Federal Urban Driving Schedules (FUDSs) profiles is carried to evaluate the model-based dynamic multi-parameter method for peak power estimation. The experimental and simulation results indicate that the model-based dynamic multi-parameter method for peak power estimation can calculate the terminal voltage and the current available power much more reliably and accurately.

[en] Boron nitride (BN) nanometer films are synthesized on Si(1 0 0) substrates by RF reactive magnetron sputtering. The surfaces of BN films are treated with hydrogen and oxygen plasma, respectively and studied by Fourier transform infrared (FTIR) spectra, atomic force microscopic (AFM) and field emission characteristics. The results show that the surface negative electron affinity (NEA) of the films is increased, the threshold field reduced and the emission current increased due to hydrogen plasma treatment. The effect of oxygen plasma treatment on field emission characteristics of BN films is obscure. The result shows that only the emission current is slightly decreased due to the surface oxidation of BN films

[en] Highlights: • The physicochemical data of extraction with mixed solvent from the WPA of hydrochloric acid route was studied. • The relation of density, viscosity, temperature and phosphoric acid concentration are expressed by different models, respectively. -- Abstract: In this study, the mixed solvent of octanol (NOA) and methyl isobutyl ketone (MIBK) was used as extractant to purify wet process phosphoric acid from hydrochloric acid route. Densities and viscosities of leachate, extraction phase and raffinate phase were determined at 293–333 K, respectively. And the relation between density and temperature or phosphoric acid concentration can be expressed as a linear equation, with the maximum deviation of 0.0011 and 0.0027 g cm⁻³, respectively. Meanwhile, the viscosity of leachate, extraction phase and raffinate phase were measured since its importance on mass transfer occurred in the process of phosphoric acid extraction. And the relation between viscosity and temperature or phosphoric acid concentration can be summarized as a unitary quadratic equation, with the maximum deviation of 0.4489 and 0.1122 mPa·s, respectively. The results show that the densities and viscosities from experiment are generally in good agreement with calculated values from those equations obtained by regression analysis. The combined expanded uncertainty in the reported densities and viscosities are 0.3% and 5.5% of the measured values respectively, each with a coverage factor, k = 2.