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Spectral asymmetry effect in terahertz generation by two-color ionizing femtosecond pulses

Physical Review A 2025年第2期111卷 023508-023508页

作者： Zhiwen Zhang Vasily A. Kostin Alexander A. Silaev Zefu Liu Shixiang Wang Chenhui Lu Zhengquan Fan Yi Liu Shanghai Key Lab of Modern Optical System University of Shanghai for Science and Technology Shanghai 200093 China Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences Nizhny Novgorod 603950 Russia Department of Control Theory Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603022 Russia Department of Electrodynamics Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603022 Russia School of Mechanical and Automotive Engineering Shanghai University of Engineering Science Shanghai 201620 China CAS Center for Excellence in Ultra-Intense Laser Science Shanghai 201800 China

Ultrabroadband intense terahertz (THz) radiation generated by two-color femtosecond pulses is a promising tool for applications in many areas involving linear and nonlinear terahertz spectroscopy and light-matter interactions. The essential challenge is to understand and control the THz spectrum in order to optimize it for specific applications. Here we study the frequency-dependent modulation of the THz spectrum with the relative phase between the second-harmonic and fundamental-field components of the linearly polarized femtosecond pulse. Analytical consideration reveals the physical reason for the suppression of the spectral modulation, which is local (induced by the local ionization dynamics and electron motion and not related to propagation effects such as phase slippage) and coherent (associated only with the phase-dependent coherent THz waveforms). The spectral modulation is sensitive to the frequency detuning, both its absolute value and the sign. Having this asymmetric dependence on the detuning, the suppressed modulation can be observed even in commensurate two-color pulses with the effect enhanced additionally by the ionization blueshift. The theoretical findings are confirmed by the experiment, where we employed chirped two-color pulses with a variable time delay between their components, effectively enabling a scan over the detuning. The obtained results show that not only the THz yield but also the spectral shape can be effectively controlled by the relative phase and may be very sensitive to a small frequency detuning arising naturally during two-color pulse propagation.

关键词： Terahertz spectroscopy

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Investigation of Ferroresonance Physical Behaviours on Three Phases Transformer with Unsymmetrical Core Leg 3

Investigation of Ferroresonance Physical Behaviours on Three...

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3rd International Seminar on Application for Technology of Information and Communication, iSemantic 2018

作者： Wahyudi, Mochammad Negara, I Made Yulistya Asfani, Dimas Anton Hernanda, I Gusti Ngurah Satriyadi Fahmi, Daniar Surabaya Indonesia Center of Excellence for Automotive Control and System ITS Indonesia

ISBN: (纸本)9781538674864

Ferroresonance still become a confusing phenomenon since its non-linear response and very high sensitivity to parameter system and flux condition of transformer core. The existence of such greatly destructive phenomenon is basically caused by an interaction among different inductances (non-linear) with a capacitance. This paper investigated the physical characteristic of ferroresonance on three phases transformer with different dimension of core leg in which the greatest dimension was at the second phase (S-phase). A variation capacitance was given in order to observe the ferroresonance behaviours, that were 10 uF, 50 uF, and 100 uF. The transformer primary voltage and its total harmonics distortion (THD) were then analyzed. The results showed that the capacitance value was not linear with the ferroresonance effect level on transformer. The highest overvoltage level was seen on the test with a capacitance of 50 uF, namely about 180 %, whereas the greatest THD value was observed on the test with a capacitance of 10 uF, namely about 18 %. Moreover, the S-phase with the greatest core leg dimension was the most susceptible to ferroresonance as the highest overvoltage level and THD value was seen on this phase. © 2018 IEEE.

关键词： Capacitance

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Application of wavelet cumulative energy and artificial neural network for classification of ferroresonance signal during symmetrical and unsymmetrical switching of three-phases distribution transformer

Application of wavelet cumulative energy and artificial neur...

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2017 International Conference on High Voltage Engineering and Power systems, ICHVEPS 2017

作者： Wahyudi, Mochammad Made Yulistya Negara, I. Anton Asfani, Dimas Gusti Ngurah Satriyadi Hernanda, I. Fahmi, Daniar Surabaya Indonesia Center of Excellence for Automotive Control and System ITS Indonesia

ISBN: (纸本)9781538609453

In the case of the presence of ferroresonance in distribution transformer due to a faulty switching operation, ferroresonance signals should be discriminated among its initiations due to opened single-phase, opened two-phases, and opened three-phases, so that ferroresonance mitigation can be conducted appropriately. However, the performance of mitigation system itself is highly determined by its accuracy in classification of such ferroresonance signals. This paper dealt with the application of wavelet cumulative energy as input of artificial neural network (ANN), that was feed-forward backpropagation network. Ferroresonance was initiated by varying grading capacitance of circuit breaker and switching operations. The fifth order of daubechies wavelet transform up to nine levels was applied to the secondary voltage of transformer. The detail signal at ninth level decomposition was then calculated its cumulative energy for the input of ANN. The ninth level detail signal and its cumulative energy showed that the ferroresonance signals were clearly distinguished between opened single-phase, opened two-phases, and opened three-phases. The ANN output also performed the satisfactory classification result. © 2017 IEEE.

关键词： Grading

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Design and Performance Analysis of Brushless DC Motor Cooling system for Low-Cost Manufacturing Process 1

Design and Performance Analysis of Brushless DC Motor Coolin...

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1st International Symposium on Advances and Innovations in Mechanical Engineering, ISAIME 2019

作者： Uta Nugraha, Yoga Cahyadi, Arief Raharjo, Juniono Nur Yuniarto, M. Wikarta, Alief Department of Electrical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Department of Naval Architechture Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Department of Mechanical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia

Thermal analysis on BLDC Motors is very important to be learned in order to obtain a low-cost motor design and have a high level of efficiency. The design of the existing motor cooling system uses a complex design that must use sophisticated machining tools and spend a lot of money in the manufacturing process. The purpose of this paper is to get the geometry of the cooling system on BLDC motor with simple manufacturing process thus saving the cost of production. The expected cooling system design is a simple geometry so that manufacturing can be done using 3-axis CNC machining. Design of cooling system using water-jacket with an additional cover. On this study, Author modeled the motor with Ansys Maxwell to obtain the heat source parameters of the motor geometry. Software Fluent is involved to perform the temperature simulation on the motor using the designed cooling system then validated with an experiment. Thermal analysis of this study compares motor performance with the use of water and oil. The flow rate compared to the radiator power efficiency. © Published under licence by IOP Publishing Ltd.

关键词： Cooling systems

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Design optimization for torque density in brushless DC motor with IPM V-type using PSO Method 1

Design optimization for torque density in brushless DC motor...

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1st International Symposium on Advances and Innovations in Mechanical Engineering, ISAIME 2019

作者： Uta Nugraha, Yoga Cahyadi, Arief Nur Yuniarto, M. Sidharta, Indra Department of Electrical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Department of Mechanical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia

The analysis model is the first stage used to determine the design parameters of the motor. It is coupled with an optimization method to find a combination of design parameters. The purpose of this paper is optimizing the torque density of the Brushless DC (BLDC) Motor with Interior Permanent Magnet (IPM) V-type. The reference design is 3-phase and 12/8 pole BLDC motor with a concentrated winding. To obtain this optimal design, this is done by eliminating the rotor area that is not covered by magnetic flux without reducing the main performance of the motor. Elimination area prediction refers to initial motor design simulation which is operated on rating condition. Mathematical modeling is based on the 2-D finite element analysis (FEA) using software Ansys Maxwell. Particle Swarm Optimization (PSO) algorithm with multi-objective function has been applied to determine the area of the rotor structure to be eliminated, resulting in an optimal torque-density design. Matlab code is also included to execute the optimization algorithm. Excitation uses the ideal sinusoidal signal by ignoring harmonic distortion. This paper features a new optimal design for IPM by considering torque density, cogging torque, harmonic distortion in back-electromagnetic force (back-EMF), and material demagnetization constraints using PSO. Quality of PSO optimization can be proven by increasing the torque density without compromising the main performance of the motor compared with FEA. With this method also provide disadvantage, such as the cost of production is more expensive because it should add a profile of the rotor mold. © Published under licence by IOP Publishing Ltd.

关键词： Brushless DC motors

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Review of the Topology and Energy Management Hybrid Energy Storage on Electric Vehicle 1

Review of the Topology and Energy Management Hybrid Energy S...

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1st International Symposium on Advances and Innovations in Mechanical Engineering, ISAIME 2019

作者： Fitri Desanti, Ayuning Uta Nugraha, Yoga Nur Yuniarto, M. Wikarta, Alief Department of Electrical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Department of Mechanical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia

There are several ways to improve the mileage of the electric vehicle (EV). High-efficiency drivetrain and high energy density are the main factors. Energy storage source for EV obtained from the battery, ultra-capacitor (UC) and fuel cells (FC). Each of that has own characteristics and capacity. The battery has a good energy density, UC and FC are superiors on power density. Combining some of the energy storage will improve performance and mileage. On this paper, the topology of combining energy storage are reviewed. In addition, also review the power management strategy of hybrid energy storage. By using a convenient strategy, hybrid energy storage becomes very worth. © Published under licence by IOP Publishing Ltd.

关键词： Fuel cells

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Comparison and Analysis of Stator Plate Holder on Yokeless and Segmented Armature Machine 2

Comparison and Analysis of Stator Plate Holder on Yokeless a...

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2nd International Conference on Electronics Representation and Algorithm: Innovation and Transformation for Best Practices in Global Community, ICERA 2019

作者： Desanti, A.F. Asfani, D.A. Yuniarto, M.N. Nugraha, Y.U. Department of Electrical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Department of Mechanical Engineering Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia

This paper deals with comparison and analysis of stator plate holder on Yokeless and segmented armature (YASA) machine. YASA topology consists of two rotors and one inner stator comprised of many independent segments. Core for stator uses Soft Magnetic Composite (SMC) to conduct the three-dimensional magnetic flux. All stator segments and concentrated winding are fixed with the aid of two annular plates. There are cavities on both plates which have the same shape as the shoe of the stator segment. Moreover, the deformation of the plates must be kept as low as possible and have very high yield strength because of stress from the bearing. A complex structure, high durability, and high electrical resistance are the challenges. Polyetheretherketone (PEEK) is usually used as the plates, however high price and manufacturing cost remain an issue. Some other materials have a possibility and approach to PEEK capability. In this paper, candidate materials will be developed as a specimen and tested on the BH-Curve meter. The BH-Curve data provide simulation on Finite Element Magnetic Method (FEMM). The advantages and disadvantages are discussed in this paper. The analysis result demonstrates that other materials possess a similar capability as PEEK related to YASA stator plate holder. © 2020 IOP Publishing Ltd. All rights reserved.

关键词： Stators

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Effect of stirring on the quality of adc 12 cast aluminium alloy 4th

Effect of stirring on the quality of adc 12 cast aluminium a...

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4th International Conference on Mechanical Engineering, ICOME 2019

作者： Agustin, H.C. Kis Sidharta, Indra Leonard Department of Mechanical Engineering ITS Indonesia Center of Excellence for Automotive Control & System ITS Indonesia

ISBN: (纸本)9783035716870

Stirring is one the most utilized process in small foundry. It is used for homogenizing the temperature and mixing process during melting. However, stirring may cause undesirable effect to the quality of castings if it is not managed properly. Bifilm is one of the defects that can be detrimental to the quality of aluminium castings, and its formation can be related to the stirring during melting. The research aim is to investigate the effect of stirring during melting of cast aluminium alloys. The quality of castings is approached by the term of bifilm index and mechanical properties. ADC 12 cast aluminium alloys is used in the experiment. The ADC 12 ingots are melted at 720 °C, and then stirred for 0, 3 and 5 minutes. Reduced Pressure Test is used for determining the bifilm index. Samples for mechanical testing are also casted into specific geometry. Results indicate that prolonged stirring time increases the bifilm index, indicating that more porosity and bifilm oxide are formed. Extended stirring time instigates more turbulence in liquid metal, hence surface oxides are folded and trapped in the bulk liquid metal. Charpy impact test, hardness test and tensile test have also carried out. More Porosity and bifilm oxide are formed in the samples and tend to decrease the mechanical property. © 2020 Trans Tech Publications Ltd, Switzerland.

关键词： Liquid metals

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Design and consideration of off-board lithium-ion battery charger for electric vehicle 1

Design and consideration of off-board lithium-ion battery ch...

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2019 1st Borobudur International Symposium on Applied Science and Engineering, BIS-ASE 2019

作者： Rusli, M.R. Mukhlisin, A. Raharjo, J. Yuniarto, M.N. Wikarta, A. Haerudin, H. Center of Excellence for Automotive Control and System Institut Teknologi Sepuluh Nopember Surabaya Indonesia Jakarta Indonesia

Recently the development and population of electric vehicles (EV) has increased significantly in line with the issue of reducing air pollution and fossil fuel dependence. EV uses batteries as the main energy source and Lithium-ion (Li-ion) batteries are more widely used by the consideration of having high energy, life cycle, and power density. As same as the ITS electric scooter which uses a Li-ion type battery pack with an operating voltage of 100 V 3.2 kWH. A battery charger has a crucial role in charging a battery pack. In this article, design, consideration, and implementation of an off-board Li-ion battery charger has been described. As a result of the proposed charger experimental test, it was capable for portable charger and producing power output up to 2.5 kW, power quality was improved through the power factor correction (PFC) which had the value above 0.75, charger efficiency was above 87%, programmable setting, temperature cut-off, and could be integrated with a battery management system (BMS) through CAN communication. The charger is expected to be reliably used for EV especially ITS electric scooters by using those features. © 2019 Published under licence by IOP Publishing Ltd.

关键词： Battery Pack

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Generalized Hebbian Algorithm for Wearable Sensor Rotation Estimation

Generalized Hebbian Algorithm for Wearable Sensor Rotation E...

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IEEE/RSJ International Conference on Intelligent Robots and systems (IROS)

作者： Joukov, Vladimir Lin, Jonathan Feng-Shun Kulic, Dana Department of Electrical Engineering Institut Teknologi Sepuluh Nopember (ITS) Surabaya Indonesia Center of Excellence for Automotive Control & System ITS

ISBN: (纸本)9781538626825

Inertial measurement units (IMUs) enable human motion measurement in any environment, which can be useful for human robot interaction, exoskeletons, and active prosthetics. This paper proposes an approach for estimating the orientation between a wearable IMU sensor and the body frame of the wearer using a simple and fast calibration procedure. The proposed approach uses the generalized Hebbian algorithm to incrementally estimate the axis aligned with gravity using acceleration measurements obtained during a static pose, and the axis perpendicular to the saggital plane using gyro measurements obtained during sagittal plane movements. An automated convergence criterion based on the sensor measurement variance is used. The proposed approach is tested in simulation and with human movement and demonstrates excellent and fast calibration performance.

关键词： Accelerometers Transmission line matrix methods Gyroscopes Convergence Robot sensing systems Principal component analysis Estimation

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