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Dispersion Monitoring Techniques in High Bit-rate Optical Communication Systems

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Semiconductor Photonics and Technology 2004年第1期10卷 8-13,20页

作者： SANGXin-zhu YUChong-xiu ZHANGQi WANGXu schoolofelectron.eng. BeijingUniversityofPostsandTelecommunicationsBeijing100876CHN

For the efficient dynamic dispersion compensation, it is essential to monitor the dispersion accurately. The existing main dispersion monitoring techniques in high bit-rate optical communication systems are presented as well as their operating principles and research progress. The advantages and disadvantages of these methods are analyzed and discussed.

关键词： Optical fiber communication Dispersion compensation Dispersion monitoring

Bragg Grating Formation in B/Ge Codoped Optical Fibers

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Semiconductor Photonics and Technology 2005年第1期11卷 5-8页

作者： SANGXin-zhu YUChong-xiu ChuPakL LaiRobust ZHANGQi schoolofelectron.eng. BeijingUniversityofPostsandTelecommunicationsBeijing100876CHN／／Optoelectron.ResearchCentreCityUniversityofHongkongTatCheeAvenueKowloonHongkongCHN schoolofelectron.eng. BeijingUniversityofPostsandTelecommunicationsBeijing100876CHN Optoelectron.ResearchCentre CityUniversityofHongkongTatCheeAvenueKowloonHongkongCHN

A 2-cm long Bragg grating with reflectivity of～99.95% in B/Ge codoped optical fiber without hydrogen loading was created by phase-mask method with a pulsed KrF excimer laser at 248 nm. DC and AC components of refractive index change were analyzed by monitoring transmission spectrum evolution during the writing process of fiber Bragg grating. The relations of the evolution of center wavelength and reflectivity with number of pulses were respectively investigated.

关键词： fiber bragg grating refractive index phase mask method

赛德西港用于船舶减排的陆上可再生能源供电评估

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哈尔滨工程大学学报（英文版） 2024年第2期23卷 506-524页

作者： Merna Makram Ameen M.Bassam Adel A.Tawfik Waleed Yehia Naval Architecture and Marine eng.Dept. Faculty of EngineeringPort Said UniversityPort Fuad 42526Egypt

Air pollution from shipping is becoming a critical issue,particularly in dense hub port *** proposed solution to minimize ship-based emissions at ports is the implementation of an Onshore Power Supply(OPS)*** allows ships to shut off their auxiliary engines and instead connect to the port *** there have been numerous studies conducted on ports in Europe and the United States,little research has been done on Egyptian ***,this paper aims to investigate the feasibility of implementing OPS at Port Said West Port in Egypt,aligning with Egypt Vision 2030’s goals for addressing climate *** research primarily focuses on analyzing data collected from calling ships to generate socio-economic and cost-effectiveness analyses of *** further enhance the environmental benefits of OPS,the paper proposes the use of solar energy as the OPS electricity *** findings of the study revealed that by relying on the national grid,emissions can be reduced by 28%.Moreover,it is predicted that this reduction could reach 100%if electricity generation is solely based on solar ***,the economic analysis demonstrates promising profitability,with a payback period of approximately two years.

关键词： Onshore power supply Port sustainability Shipping emissions inventory Solar energy Photovoltaic systems

Smart prediction of liquefaction-induced lateral spreading

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2310-2325页

作者： Muhammad Nouman Amjad Raja Tarek Abdoun Waleed El-Sekelly New York University(NYU)Abu Dhabi Abu Dhabi129188United Arab Emirates University of Management and Technology Lahore54372Pakistan Department of Civil and Environmental eng. Rensselaer Polytechnic Institute(RPI)1108th StreetJEC 4049TroyNY12180USA Department of Structural engineering Mansoura UniversityMansoura35516Egypt

The prediction of liquefaction-induced lateral spreading/displacement(Dh)is a challenging task for civil/geotechnical *** this study,a new approach is proposed to predict Dh using gene expression programming(GEP).Based on statistical reasoning,individual models were developed for two topographies:free-face and gently sloping *** with a comparison with conventional approaches for predicting the Dh,four additional regression-based soft computing models,*** process regression(GPR),relevance vector machine(RVM),sequential minimal optimization regression(SMOR),and M5-tree,were developed and compared with the GEP *** results indicate that the GEP models predict Dh with less bias,as evidenced by the root mean square error(RMSE)and mean absolute error(MAE)for training(i.e.1.092 and 0.815;and 0.643 and 0.526)and for testing(i.e.0.89 and 0.705;and 0.773 and 0.573)in free-face and gently sloping ground topographies,*** overall performance for the free-face topology was ranked as follows:GEP>RVM>M5-tree>GPR>SMOR,with a total score of 40,32,24,15,and 10,*** the gently sloping condition,the performance was ranked as follows:GEP>RVM>GPR>M5-tree>SMOR with a total score of 40,32,21,19,and 8,***,the results of the sensitivity analysis showed that for both free-face and gently sloping ground,the liquefiable layer thickness(T_(15))was the major parameter with percentage deterioration(%D)value of 99.15 and 90.72,respectively.

关键词： Lateral spreading Intelligent modeling Gene expression programming(GEP) Closed-form solution Feature importance

Big Third-order Nonlinear Optical Properties of Two Poly[(3-alkylthiophene-2, 5-diyl)-(benzylidenequinomethane-2, 5-diyl)] Derivatives

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Semiconductor Photonics and Technology 2005年第2期11卷 99-102页

作者： GAOChao WUHong-cai YIWen-hui LIBao-ming SUNJian-ping MengLing-jie schoolofelectron andInform.Eng.Xi＇anJiaotongUniversityXi＇an710049CHN schoolofelectron andInform.Eng.Xi＇anJiaotongUniversityXi＇an710049CHN

Two novel poly[(3-alkylthiophene-2,5-diyl)-(benzylidenequinomethane-2,5-diyl)s] derivatives, poly[ (3-butylthiophene-2,5-diyl)-( p-N,N-dimethylamino) benzylidenequinomethane-2,5-diyl) ] ( PBTDMABQ) and poly [( 3-octylthiophene2,5-diyl) -(p-N, N-dimethylamino ) benzylidenequinomethane-2, 5-diyl)] (POTDMABQ), were *** band gaps of the two polymers are calculated as 1. 75 eV for PBTDMABQ and 1. 69 eV for POTDMABQ,respectively. The homogenous films of the two polymers were prepared and their third-ordernonlinear optical properties were studied by the backward degenerate four-wave mixing at 532 nm. Byusing the relative measurement technique, the third-order nonlinear optical susceptibilities ofPBTDMABQ and POTDMABQ are calculated as 5. 62 X 10^(-9) and 1. 22 X 10^(-8) ESU, respectively. It isfound that substituted alky groups have strong effects on the band gap and nonlinear opticalproperties of the two polymers. The relatively big third-order nonlinear optical susceptibilitiesand small band gap of POTDMABQ resulted mainly from the longer alkyl with strong electron-donatingability can enhance the delocation degree of conjugated π electronics.

关键词： poly [( 3-alkylthiophene)-( benzylidenequinomethane)] derivatives degeneratefour-wave mixing third-order nonlinear susceptibility band gap

Influence of EDFA's Characteristics on Performance of All Optical Network

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Semiconductor Photonics and Technology 2002年第2期8卷 70-74,79页

作者： WANGTian－zhu YUCong－xiu 等 schoolofelectron Eng.BeijingUniversityofPostandCommum.Beijing10087CHN

The characteristic of EDFA in WDM system is analyzed. The simulation system based on the architecture of the China Information Network (CAINONET) is introduced, and the influence of noise figure, gain unflatness and output power of EDFA on the BER performance and scale of network is investigated. Moreover, the influence of noise figure is studied with different crosstalk . Meanwhile, it is indicated that it is important to apply the "node isolation principle" in the optical network. The research results can provide the valuable reference for the practical construction of all optical network .

关键词： EDFA WDM Optical add/drop multiplexer Optical cross-connection China information network

HIGHLY PRECISE AND FAST COMPUTATION OF THE CONTINUOUS SIGNAL PAR IN OFDM AND DMT SYSTEMS

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Journal of Electronics(China) 2005年第1期22卷 9-17页

作者： YuHua LinYaorong WeiGang schoolofelectron.＆Info.eng. SouthChinaUniv.ofTech.Guangzhou510640China

Two procedures are developed here to compute the Peak-to-Average envelope power Ratio (PAR) of the continuous signal with N subcarriers in the Orthogonal Frequency Division Multiplexing (OFDM) and Discrete MultiTone (DMT) systems. The first one is an accurate computation method for small N, in which the peak of the Instantaneous Envelope Power Function (IEPF) is obtained by solving the roots of a polynomial, a linear sum of a set of Chebyshev polynomials of the first kind and the second kind. The second procedure, called Stepwise Refinement Algorithm (SRA), is a highly precise and fast computation method for arbitrary N by using Inverse Fast Fourier Transform (IFFT), the Chirp Z-Transform (CZT) and a newly introduced relationship between the IEPF peak and its most adjacent oversampled sample.

关键词： Discrete MultiTone(DMT) Orthogonal Frequency Division Multiplexing(OFDM) Peak-to-Average envelope power Ratio(PAR)

Analysis of travelling wave solutions of double dispersive sharma-Tasso-Olver equation

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Journal of Ocean engineering and Science 2024年第5期9卷 461-474页

作者： Kamruzzaman Khan Henk Koppelaar M.Ali Akbar Syed Tauseef Mohyud-Din Department of Mathematics Pabna University of Science and TechnologyPabna 6600Bangladesh Fac.of Electrical eng. Mathematics and Comp.ScienceUniversity of DelftNetherlands Department of Applied Mathematics University of RajshahiRajshahi 6205Bangladesh Department of Mathematics HITEC University Taxila CanttPakistan School of Science and Technology University of New EnglandArmidaleNSW 2351Australia

Travelling wave solutions have been played a vital role in demonstrating the wave character of nonlinear problems arising in the field of ocean engineering and *** describe the propagation of the nonlinear wave phenomenon in the ocean(for example,wind waves,tsunami waves),a variety of evolution equations have been suggested and investigated in the existing *** paper studies the dynamic of travelling periodic and solitary wave behavior of a double-dispersive non-linear evolution equation,named the Sharma-Tasso-Olver(STO)*** evolution equations with double dispersion enable us to describe nonlinear wave propagation in the ocean,hyperplastic rods and other mediums in the field of science and *** analyze the wave solutions of this model using a combination of numerical simulations and Ansatz *** analysis shows that the travelling wave solutions involve a range of parameters that displays important and very interesting properties of the wave *** relevance of the parameters in the travelling wave solutions is also *** simulating numerically,we demonstrate how parameters in the solutions influence the phase speed as well as the travelling and solitary ***,we discuss instantaneous streamline patterns among the obtained solutions to explore the local direction of the components of the obtained solitary wave solutions at each point in the coordinate(x,t).

关键词： Travelling wave Solitary wave Streamline Enhanced(G'/G)-expansion method STO equation

Strip Waveguide Directional Coupling Modulator with Equivalent Refractive Index

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Semiconductor Photonics and Technology 2004年第4期10卷 240-244页

作者： LIHong-tao HEDui-yan KeyLab.ofMeasur.＆TestTechnol.andCommun.eng. SchoolofElectron.Inform.Eng.WuhanUniversityWuhan430079CHN

The equivalent refractive index（ERI） method is employed to analyze the function of the strip waveguide directional coupling modulator（SWM）. Through deducing the diagnostic equation of the Exmn mode of the four-layer media film waveguide equivalent to the SWM,the transmission constant of the symmetrical mode of the positive phase and negative one and the coupling length of powerful transference are obtained. The veracity of ERI is validated with the example of Ex11 basal mode under conditions of comparing the three results of ERI,EIM and Marcatili.

关键词： Guided wave optics Directional coupling modulator Strip waveguide Equivalent refractive index