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Analytic perturbation solutions to the Venusian orbiter due to the nonspherical gravitational potential

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Science China Mathematics 2000年第5期43卷 552-560页

作者：刘林 C.k.shum Department of Astronomy Nanjing University Nanjing 210093 China The Texas University at Austin Center for Space Research

The analytic perturbation solutions to the motions of a planetary orbiter given in this paper are effective for0< e< 1, where e is the orbital eccentricity of the orbiter. in the solution, it is as-sumed that the rota... 详细信息

The analytic perturbation solutions to the motions of a planetary orbiter given in this paper are effective for0kground is clear. Examples for such planets in the solar system are Ven黶 and Mercury. The perturbation solution is tested numer-ically on two Venusian orbiters with eccentric orbits, pVO and Magellan, and found to be effective.

关键词： slow rotation central body Venusian orbiter nonspherical gravitational potential analytic per- turbation solutions.

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Ortho-u-monoids

Acta Mathematica Sinica,English Series 2011年第5期27卷 831-844页

作者： Chun Mei GONG Yu Qi GUO k. p. shum Department of Mathematics Southwest University Chongqing 400715 P. R. China Department of Mathematics Xi'an University of Architecture and Technology Xi'an 7'10055 P. R. China Department of Mathematics The University of Hong Kong Hong Kong P. R. China

In this paper, we study the class of ortho-u-monoids which are generalized orthogroups within the class of E（S）-semiabundant semigroups. After introducing the concept of （-）-Green＇s relations, and obtaining some important properties of （-）-Green＇s relations and super E（S）-semiabundant semigroups, we have given the semilattice decomposition of ortho-u-monoids and a structure theorem for regular ortho-u-monoids. The main techniques that we used in the study are the （-）-Green＇s relations, and the semi-spined product of semigroups.

关键词： (-)-Green's relations super E(S)-semiabundant semigroups ortho-u-monoids semi-spin- ed products

Dynamics of cavity soliton driven by chirped optical pulses in kerr resonators

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Frontiers of Optoelectronics 2022年第1期15卷 156-163页

作者： Jianxing pan Chaoyu Xu Zhichao Wu Jing Zhang Tianye Huang perry ping shum School of Mechanical Engineering and Electronic Information China University of Geosciences(Wuhan)Wuhan 430074China Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China

Recent researches have demonstrated that pulsed driving is an effective method to increase the temporal overlap between cavity soliton(CS)and pump field,thereby increasing the pump-to-comb conversion *** amplitude-modulated inhomogeneity of the background wave causes the solitons to drift toward edges of the driving *** eliminate the mul-tiple temporal trapping positions,induced by the spontaneous symmetry breaking,we propose the chirped pulse driving for deterministic single soliton *** theoretically explain the physical mechanism of the chirp pulse driving,as the combination of amplitude and phase *** numerical simulations demonstrate the chirp is responsible for the single soliton generation.A detailed investigation for dynamics of CSs sustained by chirped pulses,shows the recovery of spontaneous symmetry *** addition,the desynchronized chirped pulse driving is also considered *** a weak chirp parameter,the desynchronization-dependent trapping position diagram is divided into multiple areas including two CSs,a single CS,two oscillating CSs,and no *** a sufficient chirp parameter considered,the trapping position curve becomes a monotonous function of the desynchronized drift velocity,which indicates deterministic single soliton generation.

关键词： Cavity soliton(CS) Chirped pulse driving Deterministic single soliton

Highly sensitive microfiber ultrasound sensor for photoacoustic imaging

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Opto-Electronic Advances 2023年第6期6卷 4-6页

作者： perry ping shum Gerd keiser Georges Humbert Dora Juan Juan Hu Aping Zhang Lei Su Department of Electronic and Electrical Engineering Southern University of Science and Technology1088 Xueyuan AvenueShenzhen 518055China Department of Electrical and Computer Engineering Boston University8 Saint Mary's StreetBoston 02215America XLIM Research Institute-UMR 7252 CNRS University of Limoges123avenue Albert ThomasLimoges 87060France Institute for Infocomm Research Agency for ScienceTechnology and Research1 Fusionopolis Way#21-01Connexis South Tower Singapore 138632Singapore The Hong kong polytechnic University Kowloon TongHong Kong 999077China School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon E14NSUK

An ultrasound wave is a kind of acoustic signal with a frequency greater than 20 kHz,which is widely used in diverse fields such as medical imaging diagnosis,nondestructive testing and resource exploration.A variety of ultrasound sensors have been developed for ultrasound *** for photoacoustic imaging,specialized ultrasound sensors with high sensitivity,small size,and broad bandwidth are ***,achieving such sensor perform-ance still poses a great challenge to the current state-of-the-art in ultrasound sensor technology.A recent work pub-lished in Opto-Electronic Advances(DOI:10.29026/oea.2022.200076)proposes a microfiber-based ultrasound sensor that breaks the limitations of existing ultrasound *** from the large evanescent field characteristic of mi-crofiber,combined with the coherent detection technology,the proposed sensor realized highly sensitive ultrasound de-tection and demonstrated excellent performance in high-resolution photoacoustic *** highly sensitive and mini-aturized microfiber ultrasound sensor provides a competitive alternative for various applications,such as endoscopic photoacoustic imaging of the intestinal tract and blood vessels in animals.

关键词： Highly sensor competitive

Fiber structures and material science in optical fiber magnetic field sensors

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Frontiers of Optoelectronics 2022年第3期15卷 55-71页

作者： Jing Zhang Chen Wang Yunkang Chen Yudiao Xiang Tianye Huang perry ping shum Zhichao Wu School of Mechanical Engineering and Electronic Information China University of Geosciences(Wuhan)Wuhan 430074China Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China

Magnetic feld sensing plays an important role in many felds of scientifc research and engineering *** from the advantages of optical fbers,the optical fber-based magnetic feld sensors demonstrate characteristics of light weight,small size,remote controllability,reliable security,and wide dynamic *** paper provides an overview of the basic principles,development,and applications of optical fber magnetic feld *** sensing mechanisms of fber grating,interferometric and evanescent feld fber are discussed in *** fuid materials,magneto-strictive materials,and magneto-optical materials used in optical fber sensing systems are also *** applications of optical fber magnetic feld sensors as current sensors,geomagnetic monitoring,and quasi-distributed magnetic sensors are *** addition,challenges and future development directions are analyzed.

关键词： Optical fber magnetic feld sensors Optical fber structures Magnetically sensitive materials Optical fber current sensors Geomagnetic monitoring Distributed magnetic felds sensors

Time-slot multiplexing based bandwidth enhancement for fiber distributed acoustic sensing

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Science China(Information Sciences) 2022年第1期65卷 292-293页

作者： Hao LI Cunzheng FAN Tao LIU Yujia LIU Zhijun YAN perry shum Qizhen SUN National Engineering Laboratory for Next Generation Internet Access System Wuhan National Laboratory for Optoelectronics School of Optical and Electronic InformationHuazhong University of Sicence and Technology Department of Electrical and Electronic Engineering Southern University of Science and Technology

Dear editor,The phase-sensitive optical time-domain reflectometry(φ-OTDR) has been demonstrated as the most common technique in fiber distributed acoustic sensing(DAS). However,traditional φ-OTDR based DAS suffered from the inherent trade-off between the maximum frequency response and the distance which can be characterized by distance bandwidth product(DBp), since the time interval of the probe pulses should be larger than the pulse round-trip flight time.

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Semi-supervised 3D shape segmentation with multilevel consistency and part substitution

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Computational Visual Media 2023年第2期9卷 229-247页

作者： Chun-Yu Sun Yu-Qi Yang Hao-Xiang Guo peng-Shuai Wang Xin Tong Yang Liu Heung-Yeung shum Institute for Advanced Study Tsinghua UniversityBeijing 100084China Microsoft Research Asia Beijing 100080China

The lack of fine-grained 3D shape segmentation data is the main obstacle to developing learning-based 3D segmentation *** propose an effective semi-supervised method for learning 3D segmentations from a few labeled 3D shapes and a large amount of unlabeled 3D *** the unlabeled data,we present a novel multilevel consistency loss to enforce consistency of network predictions between perturbed copies of a 3D shape at multiple levels:point level,part level,and hierarchical *** the labeled data,we develop a simple yet effective part substitution scheme to augment the labeled 3D shapes with more structural variations to enhance *** method has been extensively validated on the task of 3D object semantic segmentation on partNet and ShapeNetpart,and indoor scene semantic segmentation on *** exhibits superior performance to existing semi-supervised and unsupervised pre-training 3D approaches.

关键词： shape segmentation semi-supervised learning multilevel consistency

Application of Multimedia and Internet Technology in Learning Mould Design

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厦门大学学报（自然科学版） 2002年第S1期41卷 295-296页

作者： Simon S p shum Department of Multimedia and Internet Technology

With the use of multimedia which combines the use o f text, sound, images, motion video and animation, it is more efficient for studen ts to learn mould design interactively. A program is created using several multi media software to simulate the mechanism of moulding processes in order to let s tudents understand the concept of mould design. In addition, students can even access the program through the Internet. Therefore, the software is defined as Multimedia and Internet Technology (MIT) program. The MIT program consists of four sections: (i) simulation of mould mechanisms, ( ii) cooling system, (iii) material information and (iv) games for tutorials. Sec tion One covers the basic operations of different types of moulds such as two-p late mould, three-plate mould, split mould, side-core mould and mould with und ercuts. Section Two introduces different types of cooling systems such as bubble r, baffle, cooling circuits, etc. Section Three provides some useful material in formation for mould design. Section Four contains games of matching mould compon ents, mould design problem finding and multiple choice questions to test student s how much they understand mould design concept. Multimedia is highly effective particularly in teaching and learning. It changes the nature of learning itself. It makes reading dynamic by giving words an impo rtant new dimension. It allows students to see, hear and do simultaneously, thus significantly reducing average learning time. Furthermore, through cooperative learning on Internet, students can access the program, share data or search info rmation anytime anywhere. Therefore, Multimedia and Internet Technology is one o f the vital aspects to speed up the realization of information age in society.

关键词： Application of Multimedia and Internet Technology in Learning Mould Design

300 km ultralong fiber optic DAS system based on optimally designed bidirectional EDFA relays

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photonics Research 2023年第6期11卷 968-977页

作者： CUNZHENG FAN HAO LI kEQING ZHANG HUANHUAN LIU YIXIANG SUN HAOGUANG LIU BAOQIANG YAN ZHIJUN YAN DEMING LIU pERRY pING shum QIZHEN SUN School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China HUST-Wuxi Research Institute Wuxi 214174China Guangdong key Laboratory of Integrated Optoelectronics Intellisense Department of Electrical and Electronic EngineeringSouthern University of Science and TechnologyShenzhen 518055China Optics Valley Laboratory Wuhan 430074China

Optical fiber distributed acoustic sensing(DAS)based on phase-sensitive optical time domain reflectometry(φ-OTDR)is in great demand in many long-distance application fields,such as railway and pipeline safety ***,the DAS measurement distance is limited by the transmission loss of optical fiber and ultralow backscattering *** this paper,a DAS system based on multispan relay amplification is proposed,where the bidirectional erbium-doped fiber amplifier(EDFA)is designed as a relay module to amplify both the probe light and the backscattering *** the theoretical noise model,the parameters of our system are carefully analyzed and optimized for a longer sensing distance,including the extinction ratio(ER),span number,span length,and gain of erbium-doped fiber *** numerical simulation shows that a bidirectional EDFA relay DAS system can detect signals over 2500 km,as long as the span number is set to be more than *** verify the effectiveness of the scheme,a six-span coherent-detection-based DAS system with an optimal design was established,where the cascaded acoustic-optic modulators(AOMs)were used for a high ER of 104 *** results demonstrate that the signal at the far end of 300.2 km can be detected and recovered,achieving a high signal-to-noise ratio of 59.6 dB and a high strain resolution of 51.8■at 50 Hz with a 20 m spatial *** is,to the best of our knowledge,a superior DAS sensing distance with such a high strain resolution.

关键词： fiber EDFA amplifier