检索结果-内蒙古大学图书馆

Spider Structure of Photoelectron Momentum Distributions of Ionized Electrons from Hydrogen Atoms for Extraction of Carrier Envelope Phase of Few-Cycle Pulses

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Chinese Physics Letters 2020年第2期37卷 20-24页

作者： Jiu Tang Guizhong Zhang Yufei He Meng Li Xin Ding Jianquan Yao College of Precision Instrument and Optoelectronics Engineering Tianjin UniversityTianjin 300072 Key Lab of Optoelectronic Information Technology(Ministry of Education) Tianjin UniversityTianjin 300072 Key Laboratory of Operation Programming&Safety Technology of Air Traffic Management Civil Aviation University of ChinaTianjin 300300

The spider structure in the photoelectron momentum distributions(PMDs)of ionized electrons from the hydrogen atom is simulated by solving the time-dependent Schrodinger equation(TDSE).We find that the spider structure exhibits sensitive dependence on carrier envelope phase(CEP)of the few-cycle *** elucidate the striking CEP dependence of the spider structure,we select three physical parameters IL,IR,and IR/IL to quantitatively characterize the variations of the spider structure induced by altering the *** is the sum of the left half panel of the transverse cut curves(i.e.,the sum of all the negative momenta along the laser polarization direction),IR is the sum of the right half panel of the transverse cut curves(i.e.,the sum of all the positive momenta along the laser polarization direction),and IR/IL is the ratio between the two *** parameters are shown to have monotonic relation with the CEP value,which is exploited to extract the *** anticipate that our method will be useful for obtaining CEPs encoded in the spider structure of PMDs.

关键词： transverse Electron momentum

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Carrier Envelope Phase Description for an Isolated Attosecond Pulse by Momentum Vortices

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Chinese Physics Letters 2019年第6期36卷 24-28页

作者： Meng Li Gui-zhong Zhang Xin Ding Jian-quan Yao College of Precision Instrument and Optoelectronics Engineering Tianjin University Civil Aviation Meteorological Institute Key Laboratory of Operation Programming & Safety Technology of Air Traffic Management Civil Aviation University of China

As a crucial parameter for a few-cycle laser pulse, the carrier envelope phase(CEP) substantially determines the laser waveform. We propose a method to directly describe the CEP of an isolated attosecond pulse(IAP) by the vortex-shaped momentum pattern, which is generated from the tunneling ionization of a hydrogen atom by a pair of time-delayed, oppositely and circularly polarized IAP-IR pulses. Superior to the angular streaking method that characterizes the CEP in terms of only one streak, our method describes the CEP of an IAP by the features of multiple streaks in the vortex pattern. The proposed method may open the possibility of capturing sub-cycle extreme ultraviolet dynamics.

关键词： Isolated Attosecond Pulse Momentum Vortices carrier envelope phase(CEP)

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Automated early warning for ATM safety risks based on fuzzy reasoning

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Information technology Journal 2013年第17期12卷 4188-4191页

作者： Heng, Xiang Man, Liang Sino-European Institution of Aviation Engineering Civil Aviation University of China Tianjin 300300 China Tianj in Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management Civil Aviation University of China Tianjin 300300 China

The establishment of an automated risk early warning mechanism closely linked to the air traffic flow management system and information management system plays a positive role in ATM risk management. In this study, a fuzzy reasoning-based approach was proposed to effectively extract the key ATM risk factors for establishing a rapid early warning mechanism. The fuzzy IF-THEN rules were used to build up a fuzzy rule base on the base of experts' knowledge and then through a multi-input fuzzy logic, the different kinds of the unsafe models were ranked. Finally, an extraction of key attributes for ATM safety risks early warning was realized. The result is that the most important attribute is weather conditions, followed by controller's ability in handling large flows and the influences from military activities rank in the third place. The use of this approach is an exploration in the intelligent warning technology for ATM safety risks. © 2013 Asian Network for Scientific Information.

关键词： Extraction

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Electron vortices in photoionization by a pair of elliptically polarized attosecond pulses

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Chinese Optics Letters 2017年第12期15卷 6-10页

作者：李猛张贵忠赵天琪丁欣姚键铨 College of Precision Instrument and Optoelectronics Engineering Tianjin University Civil Aviation Meteorological Institute Key Laboratory of Operation Programming & Safety Technology of Air Traffic Management Civil Aviation University of China

The photoionization by two elliptically polarized, time delayed attosecond pulses is investigated to display a momentum distribution having the helical vortex or ring structuresi The results are obtained by the strong field approximation method and analyzed by the pulse decomposition. The ellipticities and time delay of the two attosecond pulses are found to determine the rotational symmetry and the number of vortex arms. For observing these vortex patterns, the energy bandwidth and temnoral duration of the attosecond pulses are ideal.

关键词： Electron vortices in photoionization by a pair of elliptically polarized attosecond pulses

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Study on returns to scale consistency between the weak BCC inefficient DMUs and their projection in DEA

Study on returns to scale consistency between the weak BCC i...

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20th International Conference on Industrial Engineering and Engineering management, IEEM 2013

作者： Lin, Wei-Feng Zhang, Bao-Cheng School of Management Tianjin University Tianjin 030072 China Tianjin Key Lab of Operation Programming and Safety Technology of Air Traffic Management No. 2898 Jinbei Road Dongli District Tianjin 300300 China

ISBN: (纸本)9783642400629

This paper discusses estimation of returns to scale (RTS) of Weak BCC inefficient DMUs in DEA. RTS generally has an ambiguous meaning if DMU is not on Weak BCC efficient frontier. Researchers adopt projection method for this problem. Theoretically, a Weak BCC inefficient DMU and its projection should exhibit the same RTS nature. Banker et al. (Eur J Oper Res 88:583-585, 1996b)'s projection, however, may give inconsistent estimation of RTS in some cases. For accurate RTS estimation of Weak BCC inefficient DMUs, this paper establishes Weak BCC projection and strong BCC projection. It is proved that, for a Weak BCC inefficient DMU, it is its Weak BCC projection that always exhibits the same RTS nature as itself while its strong BCC projection is not in some cases. In addition, Weak BCC projection is the most representative point among all frontier points for Weak BCC inefficient DMU. Therefore the projection should be Weak BCC projection, not strong BCC projection, when estimating RTS of Weak BCC inefficient DMUs. © Springer-Verlag Berlin Heidelberg 2013.

关键词： Banker's projection DEA RTS The most representative point Weak BCC inefficient DMUs Weak BCC projection

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Research on AMDB modeling and display techniques

Research on AMDB modeling and display techniques

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International Conference on Control,Mechatronics and Automation technology(ICCMAT 2014)

作者： C.Chen Y.L.Wang Z.P.Hui J.N.Wang Civil Aviation University of China Tianjin Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management

Considering the important role AMDB takes in the future air traffic management system, an AMDB data modeling method has been proposed, which is followed by a display technique. In this paper, first,the UML and XML schema model of AMDB data are constructed on which the aerodrome mapping database is based. Secon, the electronic airport map is drawn by the Auto CAD according to the AIP, NAIP, and airport design chart, which is then be rendered by 3ds MAX and checked by GLClayer. Finally, Qt is used to link the aerodrome mapping database and electronic airport map that aims to visualize the aerodrome mapping *** program presented in this paper can be used as a prototype system of commercial AMDB product.

关键词： AMDB data modeling visualization

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Characterizing carrier envelope phase of an isolated attosecond pulse with annular photoionization momentum spectra

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Chinese Optics Letters 2017年第11期15卷 1-5页

作者：李猛张贵忠赵天琪丁欣姚键铨 College of Precision Instrument and Optoelectronics Engineering Tianjin University Tianjin 300072 China Civil Aviation Meteorological Institute Key Laboratory of Operation Programming and Safety Technology of Air Traffic Management Civil Aviation University of China Tianjin 300300 China

The carrier envelope phase（CEP） has a direct impact on the physical properties of an isolated attosecond pulse（IAP） and many strong field processes,but it is difficult to measure in *** at obtaining more accurate and complete characterization of CEP,we numerically investigate the annular photoelectron momentum spectra of the hydrogen atom ionized by overlapped fields of an IAP and an infrared（IR） *** defining an overlapping parameter,the momentum patterns are classified and optimized for unambiguously measuring the rotation angle of a momentum pattern versus the CEP value.A series of simulations verify its robustness.

关键词： momentum annular overlapping photoelectron robustness overlapped rotation envelope verify reality

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4D Trajectory Tracking Control for aircraft Based on Point-to-Point Iterative Learning Control with Current-Cycle Feedback

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Transactions of Nanjing University of Aeronautics and Astronautics 2021年第6期38卷 937-947页

作者： JIANG Gaoyang WANG Hongyong College of Air Traffic Management Civil Aviation University of ChinaTianjin 300300P.R.China Tianjin Key Laboratory for Air Traffic Operation Planning and Safety Technology Tianjin 300300P.R.China

A point-to-point iterative learning control method with the current-cycle feedback is proposed to enable aircraft to achieve an accurate four-dimensional(4D) trajectory tracking. To this end,the 4D trajectory tracking control problem is formulated into a point-to-point tracking control issue with an external disturbance. Then,the optimal point-to-point iterative learning control law is derived based on the successive projection method. Further,the current-cycle feedback error is added to the control law,so that the tracking error is reduced in both time and iteration domains. Finally,a numerical simulation is carried out using the kinematic model of an unmanned aerial vehicle and 4D trajectory data. Obtained results demonstrate that the proposed method can quickly reduce the trajectory tracking error even in the presence of gust interferences. Compared with the commonly used average velocity method and the velocity correction method,the proposed method makes full use of the past and current running data,and can continuously improve the accuracy of 4D trajectory tracking with the repetitive operation of aircraft between city pairs.

关键词： four-dimentional(4D)trajectory trajectory tracking iterative learning control trajectory-based operation controlled time of arrival

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Runway Incursion Risk Assessment Based on the Monte Carlo Method

Runway Incursion Risk Assessment Based on the Monte Carlo Me...

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2015 International Conference on Advances in management Engineering and Information technology(AMEIT 2015)

作者： Z.N.Zhang Y.Q.Zhang Z.Gao National Key Laboratory of Air Traffic Operation Safety Technology Civil Aviation University of China Tianjin Station of Air Traffic Management

Runway incursion has become an important factor affecting the safe operation of the airport. This article focused on the changes of several objective factors that lead to the changes of the runway incursion risk probability. These factors are the initial position of the aircraft, aircrafts' type, and initial velocity of the aircraft and friction coefficient of the runway in different weather conditions. These factors obey different probability distributions, by using the Monte Carlo method to evaluate and eventually gave the effect of different factors on the risk of runway incursion under different weather conditions, by contrasting with the actual operation, the results showed that the assessment is feasible.

关键词： runway incursion risk assessment objective factors normal distribution Monte Carlo method

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En-route Sector Complexity Control Strategies in air traffic management

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Transactions of Nanjing University of Aeronautics and Astronautics 2021年第6期38卷 901-913页

作者： WANG Hongyong DONG Zhenzhen DENG Taotao SONG Ziqi Tianjin Key Laboratory for Air Traffic Operation Planning and Safety Technology College of Air Traffic ManagementCivil Aviation University of ChinaTianjin 300300P.R.China Department of Civil and Environmental Engineering Utah State UniversityLogan 84322USA

Along with the rapid development of air traffic, the contradiction between conventional air traffic management(ATM)and the increasingly complex air traffic situations is more severe,which essentially reduces the operational efficiency of air transport systems. Thus,objectively measuring the air traffic situation complexity becomes a concern in the field of ATM. Most existing studies focus on air traffic complexity assessment,and rarely on the scientific guidance of complex traffic situations. According to the projected time of aircraft arriving at the target sector boundary,we formulated two control strategies to reduce the air traffic complexity. The strategy of entry time optimization was applied to the controllable flights in the adjacent upstream sectors. In contrast,the strategy of flying dynamic speed optimization was applied to the flights in the target sector. During the process of solving complexity control models,we introduced a physical programming method. We transformed the multi-objective optimization problem involving complexity and delay to single-objective optimization problems by designing different preference function. Actual data validated the two complexity control strategies can eliminate the high-complexity situations in reality. The control strategy based on the entry time optimization was more efficient than that based on the speed dynamic optimization. A basic framework for studying air traffic complexity management was preliminarily established. Our findings will help the implementation of a complexity-based ATM.

关键词： air traffic management(ATM) air traffic situation air traffic control complexity-based management traffic complexity

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