[en] This paper briefly describes the development of digital I and C system in nuclear power plant, and analyses the viewpoints of NRC and other nuclear safety authorities on Software Common Cause Failure (SWCCF). In view of the SWCCF issue introduced by the digitized platform adopted in nuclear power plant safety system, this paper illustrated a diversified defence strategy for computer software and hardware. A diversified defence-in-depth solution is provided for digital safety system of nuclear power plant. Meanwhile, analysis on problems may be faced during application of nuclear safety license are analyzed, and direction of future nuclear safety I and C system development are put forward. (author)

[en] Electromagnetically induced transparency in a multilevel system is investigated in ¹⁷³Yb. The level structure investigated is ''open'' in that the light that gives rise to the transparency also resonantly couples the atoms to excited states which do not exhibit electromagnetically induced transparency. The resulting reduction of transparency is investigated experimentally and theoretically. It is found that, while the transparency is poor in certain regimes, it can be made to perform arbitrarily well in the limit of a large intensity imbalance between the optical fields.

[en] The processes of passive sampling and electret collection are discussed. Two types of passive sampling chamber have been developed in our laboratory: a passive sampling chamber with electret collection (PSCE) used for environmental radon concentration monitoring and radon flux rate measurement; and a passive sampling chamber with and without electret collection (PSCP) used as a personal radon dosemeter and area radon monitor. The lower limits of detection for radon concentration monitoring are 3.0 T ¹1,2.0 x 10² T ¹and 3.8 x 10³ T ¹Bq m ³for PSCE and PSCP with and without electret collection, respectively, where T is the sampling period in hours. The lower limit of detection for radon flux rate measurement with PSCE is 2.0 x 10 ⁴T ²Bq m ^.2s ¹. The characteristics of the passive sampling monitoring techniques and some monitoring results are described. (author)

[en] Highlights: • Multi-omics provides a comprehensive insight into microbial community in a pre-denitrification biofilter. • The expression of nitrogen metabolism genes and the activity of related enzymes were high. • There is a correlation between the biofilm microorganisms and metabolites. • Metabolic profiles of biofilms varied with layer heights. The highly complex microbial communities in biofilm play crucial roles in the pollutant removal performance of wastewater treatment plants (WWTPs). In the present study, using multi-omics analysis, we studied microbial structure, key enzymes, functional traits, and key metabolic pathways of pre-denitrification biofilter in an urban WWTP in China. The analysis results of metagenomic and metaproteomic showed that Betaproteobacteria and Flavobacteriia were dominant in biofilms. The integrated metagenomic and metaproteomic data showed that the expression of nitrogen metabolism genes was high, and the high proportion of denitrification module indicating that denitrification was the main nitrogen removal pathway. The most abundant denitrifying bacterial genera were: Dechloromonas, Acidovorax, Bosea, Polaromonas, and Chryseobacterium. And microorganisms with denitrification potential may not be able to denitrify in the actual operation of the filter. The integrated analysis of metaproteomic and metabolomic showed that there was a correlation between biofilm microorganisms and metabolites. Metabolomic analysis indicated that metabolic profiles of biofilms varied with layer height. This study provides the first detailed microbial communities and metabolic profiles in a full-scale pre-denitrification biofilter and clarifies the mechanism of denitrification.

[en] A series of binary and ternary complexes of lanthanide (Eu³⁺, Sm³⁺ and Tb³⁺) with salicylic acid (Hsal) and 1,10-phenanthroline (phen) were synthesized, and characterized by element analysis, coordination titration analysis, IR, UV and TG-DTA. Their compositions were (NH₄)[Ln(sal)₄(H₂O)₂] (Ln=Eu (1), Sm (2), Tb (3)) and (NH₄)[Ln(sal)₄(phen)₂] (Ln=Eu (4), Sm (5), Tb (6)), respectively. In particular, the ternary complex of Eu³⁺, 4, was characterized by X-ray diffraction, and luminescence intensities of binary and ternary complexes were compared. In case of Eu³⁺ and Sm³⁺ complexes, ternary complexes emitted stronger luminescence than corresponding binary complexes of salicylic acid and Ln³⁺. On the other hand, the ternary Tb³⁺ complex had weaker luminescence than the binary complex because of back energy transfer from Tb³⁺ to phen. The CIE coordinates of 1–6 were calculated as (0.65, 0.35), (0.52, 0.48), (0.33, 0.59), (0.67, 0.33), (0.62, 0.38) and (0.36, 0.58), respectively, which enable these complexes to be promising candidates for red, green, or yellow component in OLEDs.

[en] An experiment was performed to study the effect of inlet velocity ratios for 3-D temperature fluctuation caused by coaxial-jet flows based on the 3-D temperature and 2-D velocity fields. The experiment results show that the mixing behavior is completed at the bottom of test section in R<1 condition. The averaged temperatures at the bottom of the flow field are asymmetric in R< l condition, while those are symmetric in R≥1 conditions. The transient temperatures are asymmetric in these cases. With the increment of inlet velocity ratios, the gradients of cold fluid temperatures decrease in height direction, while those of hot fluid temperatures increase. In R>1 condition, the intensities of temperature fluctuations are less than those in R≤1 conditions. The strong temperature fluctuations occur in the regions between the hot and cold flow, as well as between the hot flow and environmental flow in this case. The frequencies of temperature fluctuations are less than 7 Hz. (authors)

[en] We investigate the photovoltaic effects of quartz single crystals annealed at high temperatures in ambient atmosphere. The open-circuit photovoltages and surface morphologies strongly depend on the heating treatments. When the annealing temperature increases from room temperature to 900°C, the rms roughness of quartz single crystal wafers increases from 0.207 to 1.011 nm. In addition, the photovoltages decrease from 1.994μV at room temperature to 1.551 μV after treated at 500°C, and then increase up to 9.8 μV after annealed at 900°C. The inner mechanism of the present photovoltaic response and surface morphologies is discussed. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

[en] Aiming at developing system analysis code independently, a system analysis code for pool-type fast reactor in China (SAC-CFR), with neutron kinetics model, core and hot pool model, intermediate heat exchanger model, primary and intermediate heat transport system, steam generation system, was developed based on Compaq Visual Fortran (CVF) to analyze the thermal-hydraulic characteristic of fast reactor under steady state operation. The simulation results of China Experimental Fast Reactor (CEFR) with SAC-CFR were compared with those in CEFR safety analysis report. The good agreements between them show that the present model is effective, which makes preparations for further development of transient model and plant protection and plant control system. (authors)

[en] Highlights: •Develops a systematic method for subcooled flow boiling heat transfer. •Proposes a correlation for subcooled flow boiling heat transfer of water. •New correlation predicts the database with an MAD of 9.1%. •The method is substantiated and proved to be effective. -- Abstract: A systematic method for developing correlations for subcooled flow boiling heat transfer was proposed. On the base of the method, a new correlation for subcooled flow boiling heat transfer of water is developed using a database containing 1184 data points from 14 published articles. The predictions of the new correlation agree with the database very well, with a mean absolute deviation (MAD) of 9.1% and 93.0% of the data within ±20% error band, which proves the effectiveness of the method.

[en] Spectral shift, especially blueshift, in peak position of electroluminescence (EL) spectrum of Si nanocrystal (Si-nc) with respect to its photoluminescence (PL) counterpart has been often observed. Explanations for the spectral difference are different for different EL mechanisms adopted. To gain a relevant picture of the EL process, in this work, we analyze three EL mechanisms that are mainly applied nowadays, i.e., the model of defect light emission, that of band-filling, and that of Si-nc size selection by the carrier energy. Different Si-nc samples and working conditions are designed and their EL and PL emissions monitored according to the predictions of the three models. It is concluded that the observed EL is mainly of Si-nc-related origin. The experimental results are more consistent with the model of Si-nc size selection