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Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

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Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： Ming Xia Yong-Jun Ye Shu-Yuan Liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the *** these measurement methods,the closed-loop method is frequently ***,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation *** CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and *** this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the *** consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was *** effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were *** on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion *** CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

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Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane oxidation with molecular oxygen and the active sites investigation

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 101-112页

作者： Lei Chen Yuan Sun Jinshan Chi Wei Xiong Pingle Liu Fang Hao College of Chemical Engineering National&Local United Engineering Research Centre for Chemical Process Simulation and IntensificationXiangtan UniversityXiangtan411105China

The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol(KA oil)is a challenging issue in the chemical *** present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5%***,the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency ***,we have developed a cobalt-nitrogen co-doped porous sphere catalyst,Co-NC-x(x is the Zn/Co molar ratio,where x=0,0.5,1,2,and 4)by pyrolyzing resorcinol-formaldehyde resin *** achieved 88.28%cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88%under *** results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the *** addition,Co0 and pyridinic-N are proposed to be the possible active species,and their proportion efficiently increased in the presence of Zn^(2+)*** this study,we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词： KA oil production cyclohexane selective oxidation cobalt-nitrogen co-doped porous carbon spheres metal-organic framework

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Estimating SVCV waterborne transmission and predicting experimental epidemic development:A modeling study using a machine learning approach

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Water Biology and Security 2024年第1期3卷 60-70页

作者： Jiaji Pan Qijin Zeng Wei Qin Jixiang Chu Haibo Jiang Haiyan Chang Jun Xiao Hao Feng State Key Laboratory of Developmental Biology of Freshwater Fish College of Life ScienceHunan Normal UniversityChangsha410081China College of Engineering and Design Hunan Normal UniversityChangsha410081China

Viral infectious diseases significantly threaten the sustainability of freshwater fish *** lack of studies on epidemic transmission patterns and mechanisms inhibits the development of containment strategies from the viewpoint of veterinary public *** study raises an epidemic mathematical model considering water transmission with the aim of analyzing the transmission process more *** basic reproduction number R0 was derived by the model parameter including the water transmission coefficient and was used for the analysis of the virus *** viremia of carp virus(SVCV)and zebrafish were used as model viruses and animals,respectively,to conduct the transmission *** through water was achieved by connecting two aquarium tanks with a water channel but blocking the fish movement between the *** the collected experimental data,we determined the optimal hybrid machine learning algorithm to analyze the transmission process using an established mathematical *** addition,future transmission was predicted and validated using the epidemic model and an optimal ***,the sensitivity of model parameters and the simulations of R0 variation were performed based on the modified complex epidemic *** study is of significance in providing theoretical guidance for minimizing R0 by manipulating model parameters with containment *** importantly,since the modified model and algorithm demonstrated better performance in handling freshwater fish transmission problems,this study advances the future application of transmissible disease modeling with larger datasets in freshwater fish aquaculture.

关键词： Epidemic mathematical model Hybrid machine learning algorithm Reproduction number Sensitivity analysis SVCV transmission

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中国吉松叶蜂属一新种和三个新组合(膜翅目:松叶蜂科)

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Entomotaxonomia 2024年第1期46卷 76-82页

作者：王汉男魏美才中南林业科技大学昆虫系统与进化生物学实验室湖南长沙410004 江西师范大学生命科学学院江西南昌330022

记述中国吉松叶蜂属Gilpinia Benson, 1939(膜翅目:松叶蜂科)1新种:杨氏吉松叶蜂Gilpinia yangiWang&***.该种色斑虽与其他中国吉松叶蜂相近,但锯腹片构造不同。文中还把***&Wei,2019移至松叶蜂属建立新组合Diprioninfuscalae(Wang&Wei,2019),***.;把***,1992和***,Wang&Wei,2022移至大松叶峰属建立新组合Macrodiprionmassoniana(***,1992)***.和Macrodiprionlishui(Li,Wang&Wei,2022),comb. nov.。本文还修订了中国吉松叶蜂已知种检索表。

关键词：叶蜂总科分类检索表

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Kinetics and Mechanism of Catalytic Reduction of U(Ⅵ)with Hydrazine on Platinum Catalysts in Nitric Acid Media

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Chinese Journal of Chemical Physics 2022年第5期35卷 813-822,I0012页

作者： Xiao-teng Zhang Shuai Hao Fei-fei Tang Bin Li Xian-ming Zhou Li-sheng Liu Liang-shu Xia School of Nuclear Science and Technology University of South ChinaHengyang 421001China Institute of Radiation Chemistry China Institute of Atomic EnergyBeijing 102413China

The kinetics of U(IV)produced by hydrazine reduction of U(VI)with platinum as a catalyst in nitric acid media was studied to reveal the reaction mechanism and optimize the reaction *** spin resonance(ESR)was used to determine the influence of nitric acid *** effects of nitric acid,hydrazine,U(VI)concentration,catalyst dosage and temperature on the reaction rate were also *** addition,the simulation of the reaction process was performed using density functional *** results show that the influence of oxidation on the main reaction is limited when the concentration of nitric acid is below 0.5 mol/*** reaction kinetics equation below the concentration of 0.5 mol/L is found as:−dc(UO_(2)^(2+))/dt=kc^(0.5323)(UO_(2)^(2+))c^(0.2074)(N_(2)H_(5)^(+))c^(−0.2009)(H^(+)).When the temperature is 50℃,and the solid/liquid ratio r is 0.0667 g/mL,the reaction kinetics constant is k=0.00199(mol/L)^(0.4712)/*** 20℃ and 80℃,the reaction rate gradually increases with the increase of temperature,and changes from chemically controlled to *** simulations of density functional theory give further insight into the influence of various factors on the reaction process,with which the reaction mechanisms are determined according to the reaction kinetics and the simulation results.

关键词： Uranium Reaction kinetics Electron spin resonance Hydrazine Density functional theory

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Coherent beam combination of two slab laser amplifiers based on stochastic parallel gradient descent algorithm

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Chinese Optics Letters 2011年第10期9卷 48-50页

作者：李霄董小林肖虎王小林许晓军 College of Opticelectric Science and Engineering National University of Defense Technology

Coherent beam combination （CBC） of laser arrays is an efficient way to scale brightness. We demonstrate CBC of two slab laser amplifiers based on active phase locking. Instead of the complex phase detection system, intensity detection is used and the feedback control signal is calculated based on the stochastic parallel gradient descent （SPGD） algorithm. The experimental investigation on a 101.5-W CBC of two slab amplifiers shows that the entire system in a closed loop performs well for long-time observation. A combination efficiency of nearly 81% is realized. The slab amplifier laser arrays are the coherent beams efficiently combined by active phase locking based on the SPGD.

关键词： Algorithms

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Counting of alpha particle tracks on imaging plate based on a convolutional neural network

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Nuclear Science and Techniques 2023年第3期34卷 52-63页

作者： Feng-Di Qin Han-Yu Luo Zheng-Zhong He Ke-Jun Lu Chuan-Gao Wang Meng-Meng Wu Zhong-Kai Fan Jian Shan School of Nuclear Science and Technology Hunan Provincial Key Laboratory of RadonUniversity of South ChinaHengyang 421001China School of Computer Science University of South ChinaHengyang 421001China China Institute of Atomic Energy Beijing 102413China

Imaging plates are widely used to detect alpha particles to track information,and the number of alpha particle tracks is affected by the overlapping and fading effects of the track *** this study,an experiment and a simulation were used to calibrate the efficiency parameter of an imaging plate,which was used to calculate the *** were created by using grayscale,which trained the convolutional neural network to count the alpha *** results demonstrated that the trained convolutional neural network can evaluate the alpha track counts based on the source and background images with a wider linear range,which was unaffected by the overlapping *** alpha track counts were unaffected by the fading effect within 60 min,where the calibrated formula for the fading effect was analyzed for 132.7 *** detection efficiency of the trained convolutional neural network for inhomogeneous ^(241)Am sources(2π emission)was 0.6050±0.0399,whereas the efficiency curve of the photo-stimulated luminescence method was lower than that of the trained convolutional neural network.

关键词： Imaging plate Convolutional neural network Alpha tracks counting

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An update: Epstein-Barr virus and immune evasion via microRNA regulation

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Virologica Sinica 2017年第3期32卷 175-187页

作者： Lielian Zuo Wenxin Yue Shujuan Du Shuyu Xin Jing Zhang Lingzhi Liu Guiyuan Li Jianhong Lu The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health Xiangya Hospital Central South University Cancer Research Institute School of Basic Medical Sciences Central South University Department of Microbiology School of Basic Medical Sciences Central South University

Epstein-Barr virus(EBV) is an oncogenic virus that ubiquitously establishes life-long persistence in humans. To ensure its survival and maintain its B cell transformation function, EBV has developed powerful strategies to evade host immune responses. Emerging evidence has shown that micro RNAs(mi RNAs) are powerful regulators of the maintenance of cellular homeostasis. In this review, we summarize current progress on how EBV utilizes mi RNAs for immune evasion. EBV encodes mi RNAs targeting both viral and host genes involved in the immune response. The mi RNAs are found in two gene clusters, and recent studies have demonstrated that lack of these clusters increases the CD4^+ and CD8^+ T cell response of infected cells. These reports strongly indicate that EBV mi RNAs are critical for immune evasion. In addition, EBV is able to dysregulate the expression of a variety of host mi RNAs, which influence multiple immune-related molecules and signaling pathways. The transport via exosomes of EBV-regulated mi RNAs and viral proteins contributes to the construction and modification of the inflammatory tumor *** EBV immune evasion, viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and pro-apoptosis molecules are involved. Our increasing knowledge of the role of mi RNAs in immune evasion will improve the understanding of EBV persistence and help to develop new treatments for EBV-associated cancers and other diseases.

关键词： Epstein-Barr virus(EBV) microRNAs immune evasion exosomes carcinogenesis

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Mesoporous tin oxide nanospheres for a NO_x in air sensor

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Journal of Semiconductors 2017年第2期38卷 20-25页

作者： Haonan Zhang Ming Zhuo Yazi Luo Yuejiao Chen College of Electrical and Information Engineering Hunan University Changsha 410082 China

Mesoporous tin oxide（SnO_2/ with a high surface area of 147.5 m^2/g has been successfully synthesized via self-assembly process, combining the driven forces of water-evaporation and molecular interactions. Scanning electron microscope, X-ray diffraction, transmission electron micrograph, Fourier transform infrared and BrunauerEmmett-Teller were employed to analyze the morphology and crystal structure of the as-synthesized mesoporous materials. As a gas sensor, mesoporous SnO_2 shows impressive performances towards NOx gas with high selectivity and stability as well as ultra high sensitivity about 94.3 to 10 ppm NO_x gas at 300 ℃. The best response time of the sample S-500 is about 3.4 s to 10 ppm NO_x at 450℃.

关键词： mesoporous materials tin oxide sensor nanospheres

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The supply voltage scaled dependency of the recovery of single event upset in advanced complementary metal-oxide-semiconductor static random-access memory cells

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Chinese Physics B 2013年第2期22卷 591-594页

作者：李达维秦军瑞陈书明 College of Computer National University of Defense Technology

Using computer-aided design three-dimensional simulation technology,the supply voltage scaled dependency of the recovery of single event upset and charge collection in static random-access memory cells are *** reveals that the recovery linear energy transfer threshold decreases with the supply voltage reducing,which is quite attractive for dynamic voltage scaling and subthreshold circuit radiation-hardened ***,the effect of supply voltage on charge collection is also *** is concluded that the supply voltage mainly affects the bipolar gain of the parasitical bipolar junction transistor（BJT） and the existence of the source plays an important role in supply voltage variation.

关键词： single event upset multi-node charge collection recovery ultra-low ower voltage

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