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Methods for determining unimpeded aircraft taxiing time and evaluating airport taxiing performance

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Chinese Journal of Aeronautics 2017年第2期30卷 523-537页

作者： Yu zhang qing Wang Civil and Environmental Engineering University of South Florida College of Air Traffic Management Civil Aviation University of China College of Transportation Engineer Tongji University

The objective of this study is to improve the methods of determining unimpeded（nominal） taxiing time,which is the reference time used for estimating taxiing delay,a widely accepted performance indicator of airport surface *** reviewing existing methods used widely by different air navigation service providers（ANSP）,new methods relying on computer software and statistical tools,and econometrics regression models are *** models are highly recommended because they require less detailed data and can serve the needs of general performance analysis of airport surface *** proposed econometrics model outperforms existing ones by introducing more explanatory variables,especially taking aircraft passing and over-passing into the considering of queue length calculation and including runway configuration,ground delay program,and weather *** length of the aircraft queue in the taxiway system and the interaction between queues are major contributors to long taxi-out *** proposed method provides a consistent and more accurate method of calculating taxiing delay and it can be used for ATM-related performance analysis and international comparison.

关键词： Aircraft taxiing Airport performance Econometric regression modeling Queue length Simulation analysis Taxiway system

Valuation of Stock Loans Under a Markov Chain Model

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Journal of Systems Science & Complexity 2016年第1期29卷 171-186页

作者： PRAGER David zhang qing Department of Mathematics Anderson University Department of Mathematics The University of Georgia

In recent years the use of Markov chain models to model stock price movement has received increased attention among *** chain models combine the discrete movements of a binomial tree model while retaining the Markovian properties of Brownian motion,thus allowing the best properties of both of these *** this paper,the authors consider a Markov chain model in which the underlying market is solely determined by a two-state Markov *** a Markov chain model is strikingly simple and yet appears capable of capturing various market *** proper selection of parameters,the Markov chain model can produce sample paths that are very similar *** very distinct from a classical Brownian motion,as the authors demonstrate in this *** paper studies the stock loan valuation,or the value of a loan in which a risky share of stock is used as collateral,under such a *** programming equations in terms of variational inequalities are used to capture the dynamics of the *** equations are solved in *** optimal solutions are *** examples are also reported to illustrate the results.

关键词： Closed-form solution Markov chain model stock loan

Learning topological defects formation with neural networks in a quantum phase transition

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Communications in Theoretical Physics 2024年第5期76卷 68-76页

作者： Han-qing Shi Hai-qing zhang Center for Gravitational Physics Department of Space ScienceBeihang UniversityBeijing 100191China Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China

Neural networks possess formidable representational power,rendering them invaluable in solving complex quantum many-body *** they excel at analyzing static solutions,nonequilibrium processes,including critical dynamics during a quantum phase transition,pose a greater challenge for neural *** address this,we utilize neural networks and machine learning algorithms to investigate time evolutions,universal statistics,and correlations of topological defects in a one-dimensional transverse-field quantum Ising ***,our analysis involves computing the energy of the system during a quantum phase transition following a linear quench of the transverse magnetic field *** excitation energies satisfy a power-law relation to the quench rate,indicating a proportional relationship between the excitation energy and the kink ***,we establish a universal power-law relationship between the first three cumulants of the kink numbers and the quench rate,indicating a binomial distribution of the ***,the normalized kink-kink correlations are also investigated and it is found that the numerical values are consistent with the analytic formula.

关键词： neural networks machine learning transverse-field quantum Ising model kibble-zurek mechanism

The Time and Energy Dependence of the Vela Pulsar's Pulse Profile inγ-Ray

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Research in Astronomy and Astrophysics 2022年第4期22卷 128-136页

作者： Lin-Li Yan Ming-Yu Ge You-Li tuo Ling-jun Wang qing-yong Zhou School of Mathematics and Physics Anhui Jianzhu UniversityHefeiAnhui 230601China Key Laboratory of Architectural Acoustics Environment of Anhui High Education Institutes HefeiAnhui 230601China Key Laboratory of Advanced Electronic Materials and Devices Anhui Jianzhu UniversityHefeiAnhui 230601China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China State Key Laboratory of Geographic Information Engineering Xi'an Institute of Surveying and MappingXi'an 710054China

We analyze the time and energy dependence of the Vela pulsar’s pulse profile using 13 yr observations from the Large Area Telescope on the Fermi Gamma-ray Space *** is found that the pulse profile of the Vela pulsar inγ-ray changes with *** parameterize the pulse profile and find that different shape parameters show fiuctuations rather than gradual changes with ***,these time variation trends are insignificant due to limited *** pulse profile of the Vela pulsar displays clear energy dependence inγ-*** shape parameters are accurately obtained or updated,especially the phase separations among different *** energy evolution trends are quantified for the first time,which will provide restrictions on currentγ-ray emission *** the Vela pulsar,we also find a turning point at *** and after this phase,the relative intensity of the pulse profile evolves with energy with the opposite trend.

关键词： stars:neutron (stars:)pulsars:individual(Vela) gamma-rays:stars Pulsars(1306) Gamma-ray sources(633)

Effect of Root Architecture on Structural Stability and Erodibility of Topsoils during Concentrated Flow in Hilly Loess Plateau

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Chinese Geographical Science 2015年第6期25卷 757-764页

作者： LI Qiang LIU Guobin zhang Zheng tuo Dengfeng XU Mingxiang State Key Laboratory of Soil Erosion and Dry Land Farming Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources University of Chinese Academy of Sciences Institute of Soil and Water Conservation Northwest A?F University

Traditional vegetation techniques for the control of concentrated flow erosion are widely recognized, whereas only a few studies have experimentally investigated the impacts of belowground roots on the erodibility of topsoils in semi-arid areas. To quantify the effects of root architectures on soil erodibility and its relevant structural properties, simulated flow experiments were conducted at six-week intervals from 18 July to 20 October in 2012 in the hilly Loess Plateau. Five treatments were: 1) bare(control), 2) purple alfalfa(Medicago sativa), representing tap roots(T), 3) switchgrass(Panicum virgatum), representing fibrous roots(F), 4) purple alfalfa and switchgrass, representing both tap and fibrous roots(T + F), and 5) natural recovery(N). For each treatment, soil structural properties and root characteristics were measured at an interval of six weeks. Soil anti-scouribility was calculated. Results showed that grass planting slightly reduced soil bulk density, but increased soil aggregate content by 19.1%, 10.6%, 28.5%, and 41.2% in the treatments T, F, T + F, and N, respectively. Soil shear strength(cohesion and angle of internal friction(φ)) significantly increased after the grass was planted. As roots grew, soil cohesion increased by 115.2%–135.5%, while soil disintegration rate decreased by 39.0%–58.1% in the 21 th week compared with the recorded value in the 9th week. Meanwhile, root density and root surface area density increased by 64.0%–104.7% and 75.9%–157.1%, respectively. No significant differences in soil anti-scouribility were observed between the treatments of T and F or of T + F and N, but the treatments of T + F and N performed more effectively than T or F treatment alone in retarding concentrated flow. Soil aggregation and root surface-area density explained the observed soil anti-scouribility during concentrated flow well for the different treatments. This result proved that the restoration of natural vegetation might be the most appropriat

关键词： fibrous roots tap roots root density soil structural properties soil anti-scouribility hilly Loess Plateau China

Bacterial diversity and distribution in the southeast edge of the Tengger Desert and their correlation with soil enzyme activities

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Journal of Environmental Sciences 2012年第11期24卷 2004-2011页

作者： Wei zhang Gaosen zhang Guangxiu Liu Zhibao Dong tuo Chen Manxiao zhang Paul J.Dyson Lizhe An Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China School of Life Sciences Lanzhou UniversityLanzhou 730000China Institute of Life Science College of MedicineSwansea UniversitySwansea SA28PPUK

The nature of microbial communities and their relation to enzyme activities in desert soils is a neglected area of investigation. To address this, the bacterial diversity and distribution and soil physico-chemical factors were investigated in the soil crust, the soil beneath the crust and rhizosphere soil at the southeast edge of the Tengger Desert, using the denaturing gradient gel electrophoresis of 16S rRNA genes amplified by the polymerase chain reaction. Phylogenedc analysis of the sequenced DGGE bands revealed a great diversity of bacteria. The Proteobacteria, consisting of the α, β, and γsubdivisions, were clearly the dominant group at all depths and in rhizosphere soil. Analysis of the enzyme activities indicated that the rhizosphere soil of Caragana korshinskii exhibited the highest protease and polyphenol oxidase activities, and in the soil crust there were increased activities of catalase, urease, dehydrogenase and sucrase. The bacterial community abundance closely correlated with soil enzyme activities in different soils. The presence of Cyanobacteria correlated with significant increases in protease, catalase and sucrase in the soil crust, and increased urease in the rhizosphere soil of Artemisia ordosica. The occurrence of Acidobacteria was associated with significant increases in urease, dehydrogenase, and sucrase in the rhizosphere soil of C. korshinski. The presence of γ-Proteobacteria correlated with a significant increase in polyphenol oxidase in the rhizosphere soil ofA. ordosica. The study indicated a close relationship between the soil bacterial community and soil enzymes, suggesting the necessity of further investigations into bacterial function in this desert ecosystem.

关键词： Tengger Desert DGGE 16S rRNA bacterial community soil enzyme

水肥一体化模式下不同水肥套餐对蜜柚产量、品质及经济效益的影响

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热带作物学报 2025年第1期46卷 123-134页

作者：张青孔庆波栗方亮黄煌伟福建省农业科学院资源环境与土壤肥料研究所福建福州350013 平和县土壤肥料与生态能源站福建漳州363700

通过2020—2022年定位试验,研究水肥一体化条件下不同水肥套餐对蜜柚产量、品质及经济效益等的影响,为探索和实践蜜柚水肥一体化施肥模式提供依据。对平和蜜柚高低产园分别设置4种处理方式:(1)TF(常规施肥)、(2)30%WF(30%水肥套餐)、(3)... 详细信息

通过2020—2022年定位试验,研究水肥一体化条件下不同水肥套餐对蜜柚产量、品质及经济效益等的影响,为探索和实践蜜柚水肥一体化施肥模式提供依据。对平和蜜柚高低产园分别设置4种处理方式:(1)TF(常规施肥)、(2)30%WF(30%水肥套餐)、(3)50%WF(50%水肥套餐)、(4)70%WF(70%水肥套餐)。2020—2022年定位试验结果表明:水溶肥套餐不同程度减量施肥对蜜柚产量影响差异显著,高低产园年平均产量影响均为:70%W>50%WF>TF>30%WF;高产园50%WF、70%WF处理比TF处理年平均增产率分别为12.43%、24.67;低产园50%WF、70%WF处理比TF处理年平均增产率分别为15.05%、26.80%;高、低产园蜜柚年平均产量均以70%WF处理最高(高产园67845.5 kg/hm^(2)、低产园53495.5 kg/hm^(2)),低产园增产幅度大于高产园;高、低产园中年平均次果率均以70%WF效果最佳(高产园5.71%、低产园4.67%)。高、低产园不同水溶肥套餐施肥处理对蜜柚果肉粒化率无显著影响,但对单果重、果肉重影响较为显著;且不同水溶肥套餐施肥处理蜜柚裂果率年际变异大;70%水溶肥套餐施肥明显改善了蜜柚基本农艺性状,提高单果重,降低裂果率。2021、2021年高、低产园中4种处理可溶性固形物、可溶性糖、可滴定酸度增减幅度不大,各处理间差异不显著;70%水溶肥套餐蜜柚各品质指标均为最佳。高产园50%WF、70%WF处理年平均最终净收益较TF处理分别增收30.58%、47.79%。年平均产投比以70%WF处理最高(4.29∶1),较TF处理高1.31倍。低产园50%WF、70%WF处理年平均最终净收益较TF处理分别增收40.41%、59.67%。年平均产投比以70%WF处理最高(3.63∶1),比TF处理高1.17倍;高、低产园中均以70%水溶肥套餐处理经济效益最高,低产园经济效益增幅大于高产园。水肥一体化模式下不同水肥套餐减量施肥具有提高蜜柚产量、经济效益和改善品质等效果,且在高低产园中蜜柚施用70%WF处理对提高蜜柚产量、经济效益和改善品质等效果最好,为最佳施肥处理,推荐应用。

关键词：减量施肥蜜柚质量经济效益水肥一体化

External control of qubit-photon interaction and multi-qubit reset in a dissipative quantum network

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Science China(Physics,Mechanics & Astronomy) 2021年第5期64卷 11-21页

作者： Xian-Peng zhang Li-tuo Shen Yuan zhang Luyan Sun Huaizhi Wu Zhen-Biao Yang zhang-Qi Yin Fujian Key Laboratory of Quantum Information and Quantum Optics and Deparment of Physics Fuzhou UniversitFuzhou 350116China Donostia International Physics Center Manuel de Lardizabal San Sebastian 20018Spain Centro de Fisica de Materiales Centro Mixto CSIC-UPVEHUSan Sebastian 20018Spain Key Laboratory of Material Physics Ministry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversinyZhengzhou 450052China Center for Quantum Information Institute for Interdisciplinary Information SciencesTsinghua UniversityBeijing 100084China Center for Quantum Technology Research and Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements(MOE) School of PhysicsBejing Institute of Technology.Bejing 100081China

A quantum network is a promising quantum many-body system because of its tailored geometry and controllable interaction. Here,we propose an external control scheme for the qubit-photon interaction and multiqubit reset in a dissipative quantum network,which comprises superconducting circuit chains with microwave drives and filter-filter couplings. The traditional multiqubit reset of the quantum network requires physically disconnected qubits to prevent their entanglement. However, we use an original effect of dissipation, i.e., consuming the entanglement generated by qubits’ interaction, to achieve an external control of the multiqubit reset in an always-connected superconducting circuit. The reset time is independent of the number of qubits in the quantum network. Our proposal can tolerate considerable fluctuations in the system parameters and can be applicable to higherdimensional quantum networks.

关键词： quantum computation quantum reservior engineering quantum network

Mechanistic Study of Oxidoreductase AprQ Involved in Biosynthesis of Aminoglycoside Antibiotic Apramycin

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Chinese Journal of Chemistry 2021年第7期39卷 1923-1926页

作者： Jinxiu Wang Suze Ma Wei Ding tuo Chen Qi zhang State Key Laboratory of Cryospheric Science Key Laboratory of Extreme Environmental Microbial Resources and EngineeringNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu730000 China Department of Chemistry Fudan UniversityShanghai200433 China University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiao Tong UniversityShanghai200240 China

Main observation and conclusion The aminoglycoside antibiotic apramycin contains a unique bicyclic octose moiety,and biosynthesis of this moiety involves an oxidoreductase *** other known“Q”series proteins involved in aminoglycosides biosynthesis,AprQ does not work with an aminotransferase partner,and performs a four-electron oxidation that converts a CH2OH moiety to a carboxylate group.

关键词： Biosynthesis Flavin Flavoprotein Oxidase Enzyme mechanism