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Uncertainty and sensitivity analysis of in-vessel phenomena under severe accident mitigation strategy based on ISAA-SAUP program

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Nuclear Science and Techniques 2024年第1期35卷 108-123页

作者： Hao Yang Ji-Shen Li Zhi-Ran Zhang Bin Zhang jian-qiang shan School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The phenomenology involved in severe accidents in nuclear reactors is highly ***,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce considerable ***,in recent years,the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs,known as“best estimate plus uncertainty(BEPU).”This approach aids in enhancing our comprehension of these programs and their further development and *** study concentrates on a third-generation pressurized water reactor equipped with advanced active and passive mitigation *** an Integrated Severe Accident Analysis Program(ISAA),numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant *** uncertainty parameters of the ISAA program were meticulously *** Wilks'formula,the developed uncertainty program code,SAUP,was employed to carry out Latin hypercube sampling,while ISAA was employed to execute batch *** analysis was then conducted on two figures of merit,namely hydrogen generation and the release of fission products within the pressure *** calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution,ranging from 182.784 to 330.664 kg and from 15.6 to 84.3%,*** ratio of hydrogen production to reactor thermal power fell within the range of 0.0578–0.105.A sensitivity analysis was performed for uncertain input parameters,revealing significant correlations between the failure temperature of the cladding oxide layer,maximum melt flow rate,size of the particulate debris,and porosity of the debris with both hydrogen generation and the release of fission products.

关键词： Gen-III PWR Severe accident mitigation Wilks’formula Hydrogen Fission products Uncertainty and sensitivity analysis

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Analysis of SBLOCA on CPR1000 with a passive system

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Nuclear Science and Techniques 2017年第1期28卷 64-73页

作者： Zi-jiang Yang Jun-Li Gou jian-qiang shan Pan Wu School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an 710049 China

Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of *** paper presents a passive safety system applied on CPR1000,which is a traditional generation II+ *** passive components selected are as follows:(1) the reactor makeup tanks(RMTs);(2) the advanced accumulators(A-ACCs);(3) the passive emergency feedwater system(PEFS);(4)the passive depressurization system(PDS);(5) the incontainment refueling water storage tank(IRWST).The model of the coolant system and the passive systems was established by utilizing a system code(RELAP5/MOD3.3).The SBLOCA(small-break loss of coolant) was analyzed to test the passive safety *** the SBLOCA occurred,the RMTs were *** water in the RMTs was then injected into the pressure *** RMTs' low water level triggered the PDS,which depressurized the coolant system *** the pressure of the coolant system decreased,the A-ACCs and the IRWST were put to work to prevent the uncovering of the *** results show that,after the small-break loss-of-coolant accident,the passive systems can prevent uncovering of the core and guarantee the safety of the plant.

关键词： Passive safety systems RELAP5/MOD3.3 CPR1000 SBLOCA

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One-pot and One-step Cu(0)-mediated Reversible-Deactivation Radical Polymerization of N-Isopropylacrylamide(NIPAM) in Water

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Chinese Journal of Polymer Science 2024年第1期42卷 1-6,I0004页

作者： Zi-shan Li Jing Lyu Bei Qiu Ying-Hao Li Ruth Foley Ri-jian Song Melissa Johnson qiang Geng Wen-Xin Wang Institute of Precision Medicine(AUST-IPM) Anhui University of Science and TechnologyHuainan 232001China Charles Institute of Dermatology School of MedicineUniversity College DublinDublin D04 V1W8Ireland

Copper(0)-mediated reversible-deactivation radical polymerization(Cu(0)-mediated RDRP) of the water-soluble monomer Nisopropylacrylamide(NIPAM) has been challenging with the problems of high dispersity, poor control over the molecular weights(MWs) or complex or multi reaction steps, etc. In this work, we report the well-controlled polymerization of NIPAM in water via a facile one-pot and one-step Cu(0)-mediated RDRP. The results of this approach show that the key for kicking off the Cu(0)-mediated NIPAM RDRPs is to ensure sufficient Cu~I at the very beginning, and the key to achieve a well-controlled chain growth is to provide adequate deactivation strength during the polymerization process. For NIPAM, which has a high propagation rate constant, the deactivation control can be effectively enhanced by extra adding deactivator(i.e., Cu~II) to the system. Moreover, a low reaction temperature(4 ℃) is necessary in the controlled synthesis of higher MW poly(Nisopropylacrylamide)(PNIPAM) to avoid the compromise in control caused by the phase transition from its lower critical solution temperature(LCST). Through this new kinetically controlled strategy, PNIPAMs with well-defined structure, narrow molecular weight distributions(MWDs) and varied MWs were successfully achieved.

关键词： Cu(0)-mediated RDRP N-isopropylacrylamide Propagation Deactivation Reaction parameters

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Multicolored Bipartite Ramsey Numbers of Large Cycles

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 347-357页

作者： Shao-qiang LIU Yue-jian PENG College of Mathematics and Statistics Hanshan Normal UniversityChaozhou 521041China School of Mathematics Hunan UniversityChangsha 410082China

For an integer r≥2 and bipartite graphs Hi,where 1≤i≤r,the bipartite Ramsey number br(H1,H2,…,Hr)is the minimum integer N such that any r-edge coloring of the complete bipartite graph KN;N contains a monochromatic subgraph isomorphic to Hi in color i for some 1≤i≤*** show that if r≥3;α1,α2>0,αj+2≥[(j+2)!-1]Σi=1^(j+1)α1 for j=1,2…r-2,then br(C2[α1n],C2[α2n],…,C2[αrn]=(Σ=j=1^(r)a j+o(1))n.

关键词： ramsey number bipartite ramsey number regularity lemma

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Influence of Incomplete Soil Plugs on Bearing Capacities of Bucket Foundations in Clay

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China Ocean Engineering 2024年第1期38卷 144-155页

作者： LI Hui-shan LIU Run YANG Xu LIAN Ji-jian State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300072China School of Civil Engineering Tianjin UniversityTianjin 300072China Institute of Marine Energy and Intelligent Construction Tianjin University of TechnologyTianjin 300384China

Due to the uneven seabed and heaving of soil during pumping,incomplete soil plugs may occur during the installation of bucket foundations,and the impacts on the bearing capacities of bucket foundations need to be *** this paper,the contact ratio(the ratio of the top diameter of the soil plug to the diameter of the bucket)and the soil plug ratio(the ratio of the soil heave height to the skirt height)are defined to describe the shape and size of the incomplete soil ***,finite element models are established to investigate the bearing capacities of bucket foundations with incomplete soil plugs and the influences of the contact ratios,and the soil plug ratios on the bearing capacities are *** results show that the vertical bearing capacity of bucket foundations in homogeneous soil continuously improves with the increase of the contact ***,in normally consolidated soil,the vertical bearing capacity barely changes when the contact ratio is smaller than 0.75,while the bearing capacity suddenly increases when the contact ratio increases to 1 due to the change of failure *** contact ratio hardly affects the horizontal bearing capacity of bucket ***,the moment bearing capacity improves with the increase of the contact ratio for small aspect ratios,but hardly varies with increasing contact ratio for aspect ratios larger than ***,the reduction coefficient method is proposed based on this analysis to calculate the bearing capacities of bucket foundations considering the influence of incomplete soil *** comparison results show that the proposed reduction coefficient method can be used to evaluate the influences of incomplete soil plug on the bearing capacities of bucket foundations.

关键词： bucket foundation incomplete soil plug uniaxial bearing capacity contact ratio soil plug ratio

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Spherical Confinement Generates Entropic Force to Accelerate Polymer Chain Detachment

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Chinese Journal of Polymer Science 2024年第3期42卷 407-416,I0010页

作者： Yu-shan Zheng jian-Ping Zhou Yan Xu Kai Li Mechanical Engineering Xinjiang UniversityUrumqi 830002China

To understand the dynamic process of polymer detachment, it is necessary to determine the mean detachment time of a single breakable link, which is modeled as a spring. Normally, this time can be viewed as the escape of a Brownian particle from the potential well of the spring. However, as the free dangling length of the polymer chain increases, the conformational entropy of the chain is affected by geometric confinement. It means that the wall exerts a repulsive force on the chain, resulting in accelerated link detachment from a macroscopic perspective. In this work, we investigate the effect of entropy on the detachment rate in the case where the substrate is spherical. We demonstrate that spherical confinement accelerates chain detachment both inside and outside the sphere. An analytical expression for the mean detachment time of breakable links is given, which includes an additional pre-factor that is related to the partition function. Additionally, we analyze the expressions for entropic forces inside the sphere, outside the sphere, and on a flat wall, comparing their magnitudes to explain the difference in mean detachment time.

关键词： Polymer detachment Breakable link Entropic force Mean first passage time

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Impact of initial fluctuations and nuclear deformations in isobar collisions

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Nuclear Science and Techniques 2024年第6期35卷 155-162页

作者： jian-Fei Wang Hao-Jie Xu Fu-qiang Wang Department of Modern Physics University of Science and Technology of ChinaHefei 230026China School of Science Huzhou UniversityHuzhou 313000China Strong-Coupling Physics International Research Laboratory(SPiRL) Huzhou UniversityHuzhou 313000China Department of Physics and Astronomy Purdue UniversityWest LafayetteIN 47907USA

Relativistic isobar^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zrcollisions have revealed intricate differences in their nuclear size and shape,inspiring unconventional studies of nuclear structure using relativistic heavy ion *** this study,we investigate the relative differences in the mean multiplicityR_()and the secondR_(ε2)and third-order eccentricityR_(ε3)between isobar collisions using initial state Glauber *** is found that initial fluctuations and nuclear deformations have negligible effects on R_()in most central collisions,while both are important for the R_(ε2)and R_(ε3),the degree of which is sensitive to the underlying nucleonic or sub-nucleonic degree of *** features,compared to real data,may probe the particle production mechanism and the physics underlying nuclear structure.

关键词： Relativistic isobar collisions Initial fluctuations Nuclear deformation

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Cage-confinement synthesis of MoC nanoclusers as efficient sulfiphilic and lithiophilic regulator for superior Li–S batteries

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Rare Metals 2024年第2期43卷 624-634页

作者： Xing-Yuan Zhang Mei-Na Lei shan Tian jian-Gan Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi’an710072China

High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite *** this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is *** sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite *** a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are *** study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.

关键词： Li-S batteries Nanocluster Electrocatalyst Polysulfide shuttle Li dendrites

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Automatic modulation recognition of radio fuzes using a DR2D-based adaptive denoising method and textural feature extraction

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Defence Technology（防务技术） 2024年第4期34卷 328-338页

作者： Yangtian Liu Xiaopeng Yan qiang Liu Tai An jian Dai Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China China Research and Development Academy of Machinery Equipment Beijing 100089China

The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference ***,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio *** solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is ***,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)***,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for *** DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical *** trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.

关键词： Automatic modulation recognition Adaptive denoising Data rearrangement and the 2D FFT(DR2D) Radio fuze

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Effects of land-use patterns on soil microbial diversity and composition in the Loess Plateau,China

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Journal of Arid Land 2024年第3期16卷 415-430页

作者： ZHANG jian GUO Xiaoqun shan Yujie LU Xin CAO jianjun College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730070China

In the Loess Plateau of China,land-use pattern is a major factor in controlling underlying biological ***,the process of land-use pattern was accompanied by abandoned lands,potentially impacting soil ***,limited researches were conducted to study the impacts of land-use patterns on the diversity and community of soil microorganisms in this *** study aimed to investigate soil microbial community diversity and composition using high-throughput deoxyribonucleic acid(DNA)sequencing under different land-use patterns(apricot tree land,apple tree land,peach tree land,corn land,and abandoned land).The results showed a substantial difference(Pshannon *** fungal beta-diversity was not considerably impacted by land-use patterns,fungal alpha-diversity indices varied *** relative abundance of Actinobacteriota(34.90%),Proteobacteria(20.65%),and Ascomycota(77.42%)varied in soils with different land-use *** pH exerted a dominant impact on the soil bacterial communities'composition,whereas soil available phosphorus was the main factor shaping the soil fungal communities'*** findings suggest that variations in land-use pattern had resulted in changes to soil properties,subsequently impacting diversity and structure of microbial community in the Loess *** the strong interdependence between soil and its microbiota,it is imperative to reclaim abandoned lands to maintain soil fertility and sustain its function,which will have significant ecological service implications,particularly with regards to soil conservation in ecologically vulnerable areas.

关键词： abandoned lands land-use pattern soil property diversity of soil microbe soil microbial community

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