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Rapid interrogation of special nuclear materials by combining scattering and transmission nuclear resonance fluorescence spectroscopy

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Nuclear Science and Techniques 2021年第8期32卷 67-77页

作者： Hao-yang Lan Tan Song Jia-Lin Zhang jian-liang Zhou Wen Luo School of Nuclear Science and Technology University of South ChinaHengyang 421001China National Exemplary Base for International Sci.&Tech. Collaboration of Nuclear Energy and Nuclear SafetyUniversity of South ChinaHengyang 421001China

The smuggling of special nuclear materials(SNMs)across national borders is becoming a serious threat to nuclear *** paper presents a feasibility study on the rapid interrogation of concealed SNMs by combining scattering and transmission nuclear resonance fluorescence(s NRF and t NRF)*** s NRF spectroscopy,SNMs such as^(235,238)U are excited by a wide-band photon beam of appropriate energy and exhibit unique NRF *** Carlo simulations show that one-dimensional scans can realize isotopic identification of concealed^(235,238)U when the detector array used for interrogation has sufficiently high energy *** simulated isotopic ratio^(235U/238)U is in good agreement with the theoretical value when the SNMs are enclosed in relatively thin *** interrogation is followed by t NRF spectroscopy using a narrow-band photon beam with the goal of obtaining tomographic images of the concealed *** reconstructed image clearly reveals the position of the isotope^(235)U inside an iron *** is shown that the interrogation time of s NRF and t NRF spectroscopy is one order of magnitude lower than that when only t NRF spectroscopy is used and results in a missed-detection rate of 10^(-3).The proposed method can also be applied for isotopic imaging of other SNMs such as^(239,240)Pu and^(237)Np.

关键词： Special nuclear material Nondestructive interrogation Nuclear resonance fluorescence

Comprehensive Evaluation of OxyCup Process for Steelmaking Dust Treatment Based on Calculation of Mass Balance and Heat Balance

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Journal of Iron and Steel Research International 2014年第6期21卷 575-582页

作者： Ke-jiang LI jian-liang ZHANG Zheng-jian LIU Rui MAO Tian-jun yang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Through the mass balance and thermal balance calculation for a typical OxyCup （or OxiCup） furnace process featuring a capacity of 380 kt/a of steel plant residuMs, the material flow and thermal flow diagrams were firstly obtained. Then, the performance of the main fuel in the OxyCup process, i.e. coke and carbon dust, was ana lyzed, and the results indicated that coke was mainly used as the stock column skeleton for the furnace and exothermal agent with a weak reduction ability; whereas carbon dust was mixed in the C-brick to reduce the iron oxide. In addition, the comparison between OxyCup process and traditional blast furnace process indicated that the reduction and melting processes in the OxyCup process were relatively isolated, while in the traditional blast furnace process, they were mixed with each other in the high temperature zone. Moreover, oxidizing atmosphere is necessary in part of the OxyCup furnaces to ensure the complete combustion of part of the coke, while only reducing atmosphere is al lowed in traditional blast furnaces. Finally, it was confirmed that oxygen enrichment can make a remarkable increase of the energy income and high temperature blast makes oMy a small contribution to energy income as the energy from the combustion of carbon takes up nearly 90% of the total income.

关键词： OxyCup furnace mass balance heat balanee oxygen enriehment hot blast temperature dust treatment

Thiol-acrylate Catalyst Enabled Post-Synthesis Fabrication of Liquid Crystal Actuators

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Chinese Journal of Polymer Science 2023年第10期41卷 1656-1662页

作者： Huan liang Ya-Wen Liu Hong-Tu Xu yang yang En-jian He Zhijun yang Yen Wei Yan Ji K The Key Laboratory of Bioorganic Phosphorus Chemistry&Chemical Biology(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing100084China Department of Chemistry Center for Nanotechnology and Institute of Biomedical TechnologyChung-Yuan Christian UniversityTaiwan32023China

Synthesizing orientated liquid crystal elastomers(LCEs)via the two-stage thiol-acrylate Michael addition and photopolymerization(TAMAP)reaction is extensively ***,excess acrylates,initiators,and strong stimuli are inevitably involved in the second stage ***,we simplify the strategy through taking advantage of a volatile alkaline(originally added to catalyze the thiol-acrylate addition in the first crosslinking stage).Without excess functional groups,the residual catalyst after annealing is still enough to trigger reactions of dynamic covalent bonds at a relatively mild temperature(80℃)to program the alignment of *** reversible reaction switches off by itself after this process since the catalyst gradually but totally evaporates upon *** obtained soft actuators exhibit robust actuation during repeated deformation(over 1000 times).Many shape-morphing modes can be achieved by rationally designing orientation *** strategy not only facilitates the practical synthesis of LCE actuators,but also balances the intrinsic conflict between stability and reprogrammability of exchangeable ***,the method of applying volatile catalysts has the potential to be extended to other dynamic covalent bonds(DCBs)applied to crosslinked polymer systems.

关键词： Liquid crystal elastomer Vitrimer Covalent adaptable network Soft actuator

Performance of Ag_(2)O/Ag Electrode as Cathodic Electron Acceptor in Microbial Fuel Cell

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Acta Metallurgica Sinica(English Letters) 2017年第12期30卷 1243-1248页

作者： Hong-Yan Dai Hui-Min yang Xuan jian Xian Liu Zhen-Hai liang College of Chemistry and Chemical Engineering Taiyuan University of Technology Department of Municipal and Environmental Engineering Taiyuan College Department of Chemistry Taiyuan Normal University

An Ag2O/Ag electrode was prepared through the electrochemical oxidation of sterling silver. This electrode was used as a cathodic electron acceptor in a microbial fuel cell （MFC）. The Ag2O/Ag electrode was characterized by scanning electron microscopy, X-ray powder diffraction and linear sweep voltammetry. The maximum voltage output of the MFC with the AgaO/Ag cathode was maintained at between 0.47 and 0.5 V in 100 cycles, indicating the good regenerative capacity of the Ag2O/Ag electrode. The overpotential loss for silver oxide was 0.021-0.006 V, and the maximum power output, open circuit potential and short circuit current of the MFC were 1.796 W m^-3, 0.559 V and 9.3375 A m^-3, respectively. The energy required for electrochemical reoxidation ranged from 40% to 55% of the energy produced by the MFC. Results indicated that the AgeO/Ag electrode could be used as a cathodic electron acceptor in MFCs with excellent stability.

关键词： Ag2O/Ag electrode Cathodic electron acceptor Microbial fuel cell Regenerative capacity Overpotential loss Stability

Effects of Degrees of Motion Freedom on Free-Fall of A Sphere in Fluid

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China Ocean Engineering 2018年第5期32卷 605-613页

作者： LIU Lei yang jian-min LYU Hai-ning TIAN Xin-liang PENG Tao State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration(CISSE) Shanghai 200240China

Free-fall of a sphere in fluid is investigated at a Galileo number of 204 by direct numerical simulations(DNS). We mainly focus on the effects of different degrees-of-freedom(DOFs) of the sphere motion during free-fall. The characteristics of free-fall are compared with those of flow past a fixed sphere. Additional numerical tests are conducted with constraints placed on the translational or rotational DOFs of the sphere motion to analyze different DOFs of sphere motion. The transverse motion contributes significantly to the characteristics of free-fall; it results in the retardation of the vortex shedding, leading to the decrease of the Strouhal number. In addition, the transversal sphere motion exhibits the tendency to promote the sphere rotation. On the contrary, the effects of the sphere rotation and vertical oscillations during free-fall are negligible.

关键词： free-fall direct numerical simulation degree of motion freedom

Electricity Production in Microbial Fuel Cell Subjected to Different Operational Modes

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Acta Metallurgica Sinica(English Letters) 2016年第5期29卷 483-490页

作者： Hong-Yan Dai Hui-Min yang Xian Liu Xuan jian Zhen-Hai liang College of Chemistry and Chemical Engineering Taiyuan University of Technology Department of Environmental Engineering Taiyuan College

The effects of inoculum species, substrate concentration, temperature, and cathodic electron acceptors on electricity production of microbial fuel cells （MFCs） were investigated in terms of start-up time and power output. When inoculated with aeration tank sludge, this MFC outperformed the cell that was inoculated with anaerobic sludge in terms of start-up time and power output. After running for a certain time period, the dominant populations of the two MFCs varied significantly. Within the tested range of substrate concentration （200-1800 mg L-l）, the voltage output increased and the time span of the electricity generation lengthened with increasing substrate concentration. As the temperature declined from 35 to 10 ℃, the maximum power density reduced from 2.229 to 1.620 W m-3, and anodic polarization resistance correspondingly dropped from 118 to 98 Ω. The voltage output of MFC-Cu2＋ was 0.447 V, which is slightly lower than that achieved with MFC-[Fe（CN）6]3- （0.492 V）, thereby indicating that MFCs could be used to treat wastewater con- taining Cu2＋ pollutant in the cathode chamber with removal of organics in anode chamber and simultaneous electricity generation.

关键词： Microbial fuel cells Inoculum species Cathodic electron acceptors Electricity production

An optimized sequential extraction scheme for molybdenum association in environmental samples

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Acta Geochimica 2016年第2期35卷 111-119页

作者： liang liang jian-Ming Zhu State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 People's Republic of China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083China University of Chinese Academy of Sciences Beijing 100049People's Republic of China

By comparing three sequential extraction pro- cedures, a new optimized extraction scheme for the molyb- denum association in environmental samples was proposed. Five operational steps were described as exchangeable （KH2PO4 ＋ K2HPO4： including water-soluble）, associated with organic matter （NaOH）, Fe-Mn oxides and/or carbonates （HC1）, sulfides （H2O2） and residue （HNO3 ＋ HF ＋ H2O2）. An optimized extraction scheme was com- pared with Tessier＇s procedure and the Commission of European Communities Bureau of Reference （BCR） was applied to black shales. Results showed Tessier＇s procedure gave the lowest concentration values for exchangeable molybdenum and the highest values for the residual molybdenum, which could not present the efficiency of the extraction reagents. BCR＇s procedure showed the highest values in oxidizable molybdenum and presented four fractions of molybdenum, which did not demonstrate the fractions of molybdenum in the black shales in detail. The optimized extraction scheme demonstrated a certain improvement on extraction efficiency over Tessier＇s proce- dure for the lowest residual molybdenum, and revealed morefeatured fraction information of molybdenum in black shales than BCR＇ s. Therefore, after a comparison with other two extraction procedures, the optimized extraction scheme proved suitable for the molybdenum in black shales and it also showed an accurate determination of the molybdenum in the fractions and source of bioavailable Mo.

关键词： Molybdenum Sequential extractionprocedure Black shales

Approximating Conditional Density Functions Using Dimension Reduction

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Acta Mathematicae Applicatae Sinica 2009年第3期25卷 445-456页

作者： jian-qing Fan liang Peng Qi-wei Yao Wen-yang Zhang Department of Operations Research and Financial Engineering Princeton University Princeton NJ 08540 USA School of Mathematics Georgia Institute of Technology Atlanta GA 30332-0160 USA Department of Statistics London School of Economics London WC2A 2AE UK Department of Mathematical Sciences University of Bath Bath BA2 7AY UK

We propose to approximate the conditional density function of a random variable Y given a dependent random d-vector X by that of Y given θ^τX, where the unit vector θ is selected such that the average Kullback-Leibler discrepancy distance between the two conditional density functions obtains the minimum. Our approach is nonparametric as far as the estimation of the conditional density functions is concerned. We have shown that this nonparametric estimator is asymptotically adaptive to the unknown index θ in the sense that the first order asymptotic mean squared error of the estimator is the same as that when θ was known. The proposed method is illustrated using both simulated and real-data examples.

关键词： Conditional density function dimension reduction, Kullback-Leibler discrepancy local linear regression nonparametric regression Shannon's entropy

Role of cerium dopants in MoVNbo multi-metal oxide catalysts for selective oxidation of ethane

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Journal of Rare Earths 2022年第5期40卷 753-762,I0003页

作者： Baohua Liu liang Yan Huahua Zhao jian yang Jun Zhao Huanling Song Lingjun Chou State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Suzhou Research Institute of LICP Chinese Academy of SciencesSuzhou 215123China

The effect of Ce on the structure of MoVNbCeO multi-metal oxide catalysts and the performance of ethane selective oxidation was *** multi-metal oxide catalysts with superior oxidizability exhibit high catalytic activity,and vanadium acts as the active center for ethane oxidation *** improved catalytic activity is related to the increased V^(5+) content on the catalyst surface,which results from the enhanced transformation of the electrons between V and ***,Ce effectively promotes oxygen adsorption,activation,and *** the presence of Ce can also prevent MoO_(3) formation and stabilize the Mo_(5)O_(14)-like *** addition,the catalyst with a moderate amount of Ce exhibits outstanding catalytic ***,the MVN-Ce catalyst with a Ce/V ratio of 0.1 exhibits the best performance:the total selectivity of the catalyst toward C_(2)H_(4) and CH_(3) COOH is the highest(72%) at the ethane conversion of 31%.Therefore,MoVNbCeO multi-metal oxides are promising candidates for selective oxidation.

关键词： Ethane oxidation Redox Mo5O14 Ce Active oxygen Rare earths