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Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

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Nuclear Science and Techniques 2024年第4期35卷 136-143页

作者： Yang Zhang Sheng-Quan Yan Ming He Qing-Zhang Zhao Wen-Hui Zhang Chao-Xin Kan Jian-Ming Zhou Kang-Ning Li Xiao-Fei Wang Jian-Cheng Liu Zhao-Hua Peng Zhuo Liang Ai-Ling Li Jian Zheng Qi-Wen Fan Yun-Ju Li You-Bao Wang Zhi-Hong Li Yang-Ping Shen Ding nan Wei nan Yu-Qiang Zhang Jia-Ying-Hao Li Jun-Wen Tian Jiang-Lin Hou Chang-Xin Guo Zhi-Cheng Zhang Ming-Hao Zhu Yu-Wen Chen Yu-Chen Jiang Tao Tian Jin-Long ma Yi-Hui Liu Jing-Yu Dong Run-Long Liu mei-yue-nan ma Yong-Shou Chen Wei-Ping Liu Bing Guo China Institute of Atomic Energy P.O.Box 275(10)Beijing 102413China College of Science Southern University of Science and TechnologyShenzhen 518055China School of Physics Xi’an Jiaotong UniversityXi’an 710049China

The Moon provides a unique environment for investigating nearby astrophysical events such as *** samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)*** this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy *** particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the ***,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS *** results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)*** sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

关键词： Accelerator mass spectrometry Wien filter Isobar separation Supernovae Chang'e-5 lunar samples

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Several variants of the Dumont differential system and permutation statistics

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Science China mathematics 2019年第10期62卷 2033-2052页

作者： Shi-mei ma Toufik mansour David GLWang Yeong-nan Yeh School of mathematics and Statistics Northeastern University at QinhuangdaoQinhuangdao066000 Department of mathematics University of HaifaHaifa3498838 School of mathematics and Statistics Beijing Institute of TechnologyBeijing102488 Institute of mathematics Academia SinicaTaipei10617

The Dumont differential system on the Jacobi elliptic functions was introduced by Dumont(1979)and was extensively studied by Dumont, Viennot, Flajolet and so on. In this paper, we first present a labeling scheme for the cycle structure of permutations. We then introduce two types of Jacobi pairs of differential equations. We present a general method to derive the solutions of these differential equations. As applications,we present some characterizations for several permutation statistics.

关键词： Jacobi elliptic functions Dumont differential system permutation statistics context-free grammars

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Recent advances in cycloaddition of CO_(2) with epoxides:halogen-free catalysis and mechanistic insights

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Frontiers of Chemical Science and Engineering 2023年第12期17卷 1879-1894页

作者： Jiaxin Li Chengguang yue Wenhao Ji Bangman Feng mei-Yan Wang Xinbin ma School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology of Ministry of EducationCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin 300072China Zhejiang Institute of Tianjin University Ningbo Key Laboratory of Green Petrochemical Carbon Emission Reduction Technology and EquipmentNingbo 315200China

The atom-economical cycloaddition of CO_(2) with epoxides to synthesize cyclic carbonates is a promising route for valuable utilization of CO_(2).Halogenide such as alkali metal halides and quaternary ammonium salt have been developed as the efficient ***,the spilled halogen causes equipment corrosion and affects the product *** address these concerns,the halogen-free cycloaddition of CO_(2) with epoxides has always been *** this review,we systematically discussed the halogen-free catalysis for cycloaddition of CO_(2) with epoxides from the mechanistic insights,aiming to promote the development of efficient halogen-free *** types of catalysts,i.e.,alternatives of halogen nucleophiles for epoxide activation,and bifunctional catalysts with Lewis acid-base sites for synergistic activation of CO_(2) and epoxides are summarized and ***,metal oxides as the potential halogen-free catalysts are highlighted due to their flexible acid-base sites for synergistic activation of CO_(2) and epoxides,facile preparation,and low cost.

关键词： carbon dioxide halogen-free catalysis cyclic carbonate mechanistic insight

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Service Life Design for Concrete Engineering in marine Environments of Northern China Based on a Modified Theoretical Model of Chloride Diffusion and Large Datasets of Ocean Parameters

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Engineering 2022年第10期17卷 123-139页

作者： Taotao Feng Hongfa Yu Yongshan Tan Haiyan ma mei Xu Chengjun yue Department of Civil and Airport Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China School of materials Science and Engineering Southeast UniversityNanjing 211189China College of Civil Science and Engineering Yangzhou UniversityYangzhou 225127China

In this study,through experimental research and an investigation on large datasets of the durability parameters in ocean engineering,the values,ranges,and types of distribution of the durability parameters employed for the durability design in ocean engineering in northern China were *** on a modified theoretical model of chloride diffusion and the reliability theory,the service lives of concrete structures exposed to the splash,tidal,and underwater zones were *** concrete proportions meeting the requirement of a service life of 100 or 120 years were designed,and a cover thickness requirement was *** addition,the effects of the different time-varying relationships of the boundary condition(Cs)and diffusion coefficient(Df)on the service life were compared;the results showed that the time-varying relationships used in this study(i.e.,Cscontinuously increased and then remained stable,and Dfcontinuously decreased and then remained stable)were beneficial for the durability design of concrete structures in marine environment.

关键词： Large datasets Modified theoretical model Reliability theory Service life Boundary condition Diffusion coefficient

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Allelic variation in the coumarate 3-hydroxylase gene associated with wood properties of Catalpa fargesii Bur.

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Journal of Forestry Research 2021年第6期32卷 2517-2529页

作者： nan Lu Fang mei Zhi Wang nan Wang Yao Xiao Lisheng Kong Guanzheng Qu Wenjun ma Junhui Wang Key Laboratory of Tree Genetics and Breeding Key Laboratory of Tree Breeding and Cultivation of State Forestry AdministrationResearch Institute of ForestryChinese Academy of ForestryBeijing 100091People’s Republic of China Department of Biology Centre for Forest BiologyUniversity of Victoria3800 Finnerty RoadVictoriaBCCanada State Key Laboratory of Tree Genetics and Breeding Northeast Forestry UniversityHarbin 150040People’s Republic of China

Coumarate 3-hydroxylase(C3h)genes participate in the synthesis of lignin and may affect the properties of wood that are important for its commercial value.A better understanding of the natural variation in C3h genes and their associations to wood properties is required to effectively improve wood *** used a candidate gene-based association mapping approach to identify CfC3h allelic variants associated with traits that affect the wood properties of Catalpa *** first isolated the full-length CfC3h cDNA(1825 bp),which was expressed at relatively high levels in xylem according to real time-polymerase chain *** totally,17 common single-nucleotide polymorphisms(minor allele frequency>5%)were identified through cloning and sequencing the CfC3h locus from a mapping population(including 88 unrelated natural *** individuals collected from main distribution area).Nucleotide diversity and linkage disequilibrium(LD)in CfC3h indicate that CfC3h has low nucleotide diversity(π_(t)=0.0031 andθ_(w)=0.0103)and relatively low LD(within 1800 bp;r^(2)≥0.1).An association analysis identified eight common single-nucleotide polymorphisms(SNPs)(false discovery rate,Qmapping population were comprised in the association population).Our study would provide new insight into C3h gene affecting wood quality,and the SNP markers identified would have potential applications in marker-assisted breeding in the future.

关键词： Catalpa fargesii Coumarate 3-hydroxylase Haplotype-based association analyses Linkage disequilibrium Single-nucleotide polymorphisms Wood properties

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L^p Approximation Capability of RBF Neural Networks

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Acta mathematica Sinica,English Series 2008年第9期24卷 1533-1540页

作者： Dong nan Wei Wu Jin Ling Long Yu mei ma Lin Jun Sun Applied mathematics Department Dalian University of TechnologyDalian116024P.R.China Department of Computer Dalian Nationalities UniversityDalian116600P.R.China

L p approximation capability of radial basis function (RBF) neural networks is investigated. If g: R +1 → R 1 and $g(\parallel x\parallel _{R^n } )$g(\parallel x\parallel _{R^n } ) ∈ L loc p (R n ) with 1 ≤ p mate any given function in L p (K) with any accuracy for any compact set K in R n , if and only if g(x) is not an even polynomial.

关键词： neural networks radial basis function L p approximation capability

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新型抗癫痫发作药物吡仑帕奈添加治疗0~18岁儿童难治性癫痫的临床观察研究

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中国全科医学 2025年第2期28卷 250-256页

作者：马湖萍任蓉侯梅苑爱云青岛大学附属妇女儿童医院神经康复科山东省青岛市266034 山东省潍坊市寿光市人民医院新生儿科 262700

背景目前儿童难治性癫痫(RE)仍是癫痫的治疗难点,国内吡仑帕奈(PER)治疗儿童RE尚属新药,缺少PER对儿童RE添加治疗的建议,且国内报道中使用PER治疗的RE患儿样本量较少。因此PER对于儿童RE,尤其低年龄RE患儿的疗效仍需大样本、进一步研究... 详细信息

背景目前儿童难治性癫痫(RE)仍是癫痫的治疗难点,国内吡仑帕奈(PER)治疗儿童RE尚属新药,缺少PER对儿童RE添加治疗的建议,且国内报道中使用PER治疗的RE患儿样本量较少。因此PER对于儿童RE,尤其低年龄RE患儿的疗效仍需大样本、进一步研究。目的探究PER添加治疗儿童RE的疗效、可能的适应证、不良反应及耐受性。方法对2022年1月—2023年1月在青岛大学附属妇女儿童医院诊治的0~18岁RE患儿进行自身对照、回顾性分析,对比PER添加治疗前后不同观察时点的癫痫发作频率的变化,评估PER的治疗效果,记录药物不良反应及药物保留率,并分析PER有效组与无效组的临床特征。结果共纳入192例研究对象,PER添加治疗后,第12、24、36周的有效率分别为56.3%(108/192)、62.1%(113/182)、69.7%(122/175),无发作率分别为19.3%(37/192)、21.4%(39/182)、24.6%(43/175)。不良反应发生率为16.1%(31/192),主要为头晕、暴躁易怒、无力嗜睡等,末次随访药物保留率为91.1%(175/192)。PER添加治疗的RE患儿连续用药12周时,治疗总有效与无效/恶化患儿起病年龄、抗癫痫治疗病程、起源类型、发作形式、添加PER前发作频率、联合其他抗癫痫发作药物(ASMs)数量、生酮饮食/外科治疗情况,差异有统计学意义(P<0.05)。此外,178例患儿进行了脑电图检查,167例患儿进行了头颅磁共振检查;治疗总有效与无效/恶化患儿脑电图检查结果、头颅磁共振检查结果比较,差异有统计学意义(P<0.05)。脑电图检查结果中以脑前部(前、中、颞前、中部)放电总有效占比较高;头颅影像学检查结果中以正常者总有效占比较高,其次为以脑白质损伤为主的患儿。结论PER添加治疗儿童RE整体有效率及保留率较高,不良反应轻微,药物耐受情况好。对于起病年龄晚、发作形式为运动性发作、局灶性起源、抗癫痫治疗病程短、联合用药数量及发作频率少的RE患儿更为有效。脑电图中以脑前部(前、中、颞前、颞中部)放电、头颅磁共振结果正常者总有效占比较高。

关键词：难治性癫痫儿童吡仑帕奈治疗结果药物不良反应

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Chemistry and Process Optimization of V-Microalloyed N80-Class Seamless Casing Tube

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Journal of Iron and Steel Research International 2010年第3期17卷 72-78页

作者： PAN Tao YANG Cai-fu ma yue XUE Dong-mei ZHANG Yong-quan Division for Structural materials Central Iron and Steel Research Institute Beijing 100081 China

The complex effects of different nitrogen （N） contents and thermal routines on the microstructure and mechanical properties of 33Mn2V steels for N80-Class seamless casing tube application were investigated using Gleeble simulation technique. The results showed that the N additions of 0. 014 %- 0. 021 % in the steels for the in-line normalization process （ILNP） increased the strength while the toughngss remained at a high level as compared with the steel with N content of 0. 005 %. It was also revealed that the N addition of 0. 021%could enhance the performance combination of strength and toughness in the steels by using 700 ℃ as the cooling interrupted temperature （CIT） for the non in-line normalizing process （NILNP）. It was further evidenced that the toughness was improved at expense of strength to some degree in all the steels by decreasing reheating temperature for the ILNP, while an increase of CIT for NILNP severely impaired the toughness and slightly improve the strength in the high-N steel with N content of 0. 021%. This can be attributed to the dissolution and precipitation behavior of V（C,N）. The optimization of V （C,N） precipitation could be achieved by enhancing N. The precipitation of V（C, N） in austenite was promoted by cooling to a certain temperature lower than the A,1 for the ILNP. The V（C,N） particles formed in austenite contrib- uted to grain refinement by the VN-induced nucleation of intragranular ferrite, but as a result the effect of precipitation on strengthening would become weaker due to a decrease of the precipitation of V in ferrite.

关键词： seamless tube in-line normalizing V-N microalloying reheating mechanical properties Gleeble simulation

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Side-lobe constrained beamforming under virtual expansion of L-shaped array

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The Journal of China Universities of Posts and Telecommunications 2021年第2期28卷 79-88页

作者： ma Shexiang mei Xiaobing School of Electrical and Electronic Engineering Tianjin University of TechnologyTianjin 300384China

To reduce the side-lobe level of L-shaped expansion array and improve the output signal to interference and noise ratio(SINR),the algorithm of side-lobe constraint based on minimum variance distortionless response(MVDR-SC)is ***,the approach of mixing diagonal loading and mailloux-Zatman(DLMZ)is used to taper the covariance matrix of the expansion ***,the second order cone programming(SOCP)obtained by constructing a new matrix is used to control the beam ***,the new adaptive weight numbers are constructed by adjusting the proportion between DLMZ and *** results show that the MVDR-SC algorithm can effectively reduce the side-lobe of beamforming under the L-shaped expansion array and obtain a larger output *** the same time,it has good robustness to the mutual coupling error.

关键词： beamforming L-shaped expansion array side-lobe constraint second order cone programming(SOCP)

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Self-feedback LSTM regression model for real-time particle source apportionment

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Journal of Environmental Sciences 2022年第4期34卷 10-20页

作者： Wei Wang Weiman Xu Shuai Deng Yimeng Chai Ruoyu ma Guoliang Shi Bo Xu mei Li yue Li Trusted AI System Laboratory College of Computer ScienceNankai UniversityTianjin 300350China KLMDASR Tianjin Key Laboratory of Network and Data Security TechnologyTianjin 300350China State Environmental Protection Key Laboratory of Urban Ambient Air Particulate matter Pollution Prevention and Control College of Environmental Science and EngineeringNankai UniversityTianjin 300071China Institute of mass Spectrometry and Atmospheric Environment Guangdong Provincial Engineering Research Center for on-line source apportionment system of air pollution Jinan UniversityGuangzhou 510632China Guangdong-Hongkong-macao Joint Laboratory of Collaborative Innovation for Environmental Quality Guangzhou 510632China

Atmospheric particulate matter pollution has attracted much wider attention *** recent years,the development of atmospheric particle collection techniques has put forwards new demands on the real-time source apportionments *** demands are summarized,in this paper,as how to set up new restraints in apportionment and how to develop a non-linear regression model to process complicated circumstances,such as the existence of secondary source and similar *** this study,we firstly analyze the possible and potential restraints in single particle source apportionment,then propose a novel three-step self-feedback long short-term memory(SF-LSTM)network for approximating the source *** proposed deep learning neural network includes three modules,as generation,scoring and refining,and regeneration *** from the scoring modules,SF-LSTM implants four loss functions representing four restraints to be followed in the apportionment,meanwhile,the regeneration module calculates the source contribution in a non-linear *** results show that the model outperforms the conventional regression methods in the overall performance of the four evaluation indicators(residual sum of squares,stability,sparsity,negativity)for the ***,in short time-resolution analyzing,SF-LSTM provides better results under the restraint of stability.

关键词： Time series Regression Self-feedback LSTM network Particle source apportionment

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