Digital Commons Network^™

Predicting Radiated Emissions From An Electrical Drive System, Giorgi Tsintsadze, Haran Manoharan, Daryl G. Beetner, Daniel Commerou, Brain Booth, Kerry Martin

Electrical and Computer Engineering Faculty Research & Creative Works

A Measurement-Based SPICE Model is Proposed to Predict Radiated Emissions from an Electrical Drive System over a Frequency Range from 20-300 MHz. the Model Combines a Model for the Radiated Emissions from the Cabling and Housings with a Model for Coupling Inside the Electrical Motor. the Electromagnetic Properties of the Cabling and Housings Were Captured with Measured S-Parameters. the Coupling Mechanisms Inside the Electrical Machine Were Represented using a Circuit- Element based Model. the Intent is to Provide Insight into How Coupling Mechanisms and Placement of Structures in the Motor Affect Radiated Emissions from the Drive System, and to Give …

Design Of Wideband Decoupling Networks For Mimo Antennas Based On An N-Ary Optimization Algorithm, Min Li, Kwan Lawrence Yeung, Lijun Jiang, Ross Murch

Electrical and Computer Engineering Faculty Research & Creative Works

Techniques for reducing the coupling between antenna elements in multiple-input multiple-output (MIMO) systems are important for achieving the full potential of MIMO. In this article, a general and systematic method is developed to design a wideband decoupling and matching network (DMN) for MIMO antenna arrays. The DMN is formed by grid-like transmission lines interconnected by lumped components, whose reactance can be obtained from an N-ary optimization algorithm. Four design benchmarks are performed for validating decoupling methodology, elaborating on design/implementation procedure, and demonstrating superiority of the proposed method. Results show that the DMN achieves broad isolation bandwidth while occupying a small …

Novel Cma Scheme To Design Self-Decoupled Mimo Dipole Pair For Base-Station Applications, Min Li, Bing Xiao, Changfei Zhou, Di Wu, Kwan Lawrence Yeung, Lijun Jiang, Ross Murch

Electrical and Computer Engineering Faculty Research & Creative Works

This article presents a novel method to design multiple-input-multiple-output (MIMO) antennas based on characteristic mode analysis (CMA), which is different from using individual excitation of each characteristic mode for high isolation. The CMA is performed to design a pair of symmetric slots on two connected dipole antennas (a MIMO dipole pair), so that two desired characteristic modes can be generated at the same frequency, one of which is in common mode and the other in differential mode. Hence, when one antenna element is excited, the two characteristic modes combine and cancel each other at the other antenna element, leading to …

De-Embedding For Coupled Three-Port Devices, Yuandong Guo, Bo Pu, Donghyun Kim, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

In many applications, the device under test (DUT) is embedded into a test setup. Various de-embedding techniques have been proposed to expose the real electrical behaviors of a DUT, e.g., the traditional thru-reflect-line and short-open-load-thru algorithms, where the T-matrix and its inverse form are adopted in the mathematical process. In the fields of radiofrequency and electromagnetic compatibility, a DUT may have three coupled ports, and the symmetry in the associated S-matrix breaks down, because the numbers of entry and exist ports are not equal, which results in a non-square T-matrix based upon the definitions. Given that the inverse expression of …

Dual-Band Decoupling Network For Mimo Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel method to design a decoupling network (DN) to increase isolation between dual-band antennas. The DN design is based on the scattering matrix and optimized by the Genetic Algorithm (GA). The decoupling example shows that the DN offers impedance matching and high isolation within desired bands, verifying the concept.

A General Coupling Methodology For Unsteady Aerostructural Optimization With Analytic Derivatives, Taylor Mcdonnell, Adam Cardoza, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Multidisciplinary design optimization offers a comprehensive approach for designing complex aerostructural systems such as wind turbines. Gradient-based multidisciplinary design optimization can be used to optimize complex systems using large numbers of design variables. However, the convergence of gradient-based optimization methods to an optimal solution is highly dependent on the accuracy of the provided derivatives. In this paper, we propose a general method for creating unsteady coupled systems for steady-state, eigenvalue, and time-domain analyses. We then describe how highly accurate derivatives may be obtained from these analyses using a combination of automatic differentiation and analytic methods (including the unsteady adjoint). Finally, …

A Fast Cascading Method For Predicting The Coupling From External Plane Waves To Pcbs, Shengxuan Xia, James Hunter, Aaron Harmon, Mohamed Z.M. Hamdalla, Ahmed M. Hassan, Chulsoon Hwang, Victor Khilkevich, Daryl G. Beetner

Electrical and Computer Engineering Faculty Research & Creative Works

The radio frequency (RF) coupling to electronic devices impacts their EMC performance. The functionalities of a working electronic device may be disrupted when the electromagnetic (EM) coupling reaches a certain level. Studies of the EM coupling to printed circuit boards (PCBs) are therefore essential for RF susceptibility and EMC purposes. For decades, researchers focused on the analytical modeling of EM coupling to transmission lines. However, when it comes to more realistic PCBs the analysis usually still relies heavily on full-wave simulations because of the complexity of the structures and the lack of analytical solutions. Using a traditional full-wave modeling approach, …

Design Of Dual-Band Decoupling Network For Two Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a dual-band decoupling network for two antennas. Design formulas are derived with systematic design procedures. Two benchmarks are presented to elaborate on the design procedure. Results show that the network offers impedance matching, high isolation, and high efficiency at both frequencies, verifying the proposed concept and theory.

A General And Systematic Method To Design Neutralization Lines For Isolation Enhancement In Mimo Antenna Arrays, Min Li, Lijun Jiang, Kwan Lawrence Yeung

Electrical and Computer Engineering Faculty Research & Creative Works

A general and systematic approach is the first time proposed in this paper to design the neutralization line (NL) for isolation enhancement in multiple-input multiple-output (MIMO) antenna arrays. Each NL consists of a metal strip and a reactive component attached at its middle position. It is connected with every two antenna radiators to generate an additional coupling path against the original antenna coupling for isolation enhancement. A general network model that leads to a systematic design procedure is developed to meet the required isolation criteria. Three practical examples are presented and used to verify the proposed NL-based decoupling technique (DT). …

Ultrahigh Electromechanical Coupling And Its Thermal Stability In (Na1/2bi1/2)Tio3-Based Lead-Free Single Crystals, Chao Chen, Li Yang, Xingan Jiang, Xiaokun Huang, Xiaoyi Gao, Na Tu, Kaizheng Shu, Xiangping Jiang, Shujun Zhang, Haosu Luo

Australian Institute for Innovative Materials - Papers

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. In this work, we report the ultrahigh electromechanical coupling performance of NBT-6BT-KNN lead-free single crystal at room temperature. The thickness mode electromechanical coupling coefficient (kt) and the 31 mode electromechanical coupling coefficient (k31) reach 69.0% and 45.7%, respectively, which are superior to the PZT-5H lead-based ceramics of kt ~ 60% and k31~39%. In addition, the evolution of the crystal structure and domain morphology is revealed by Raman scattering spectra, a polarizing microscope and piezoelectric force microscopy characterization.

Coupling N2 And Co2 In H2o To Synthesize Urea Under Ambient Conditions, Chen Chen, Xiaorong Zhu, Xiaojian Wen, Yangyang Zhou, Ling Zhou, Hao Li, Li Tao, Qiling Li, Shiqian Du, Tingting Liu, Dafeng Yan, Chao Xie, Yuqin Zou, Yanyong Wang, Ru Chen, Jia Huo, Yafei Liu, Jun Cheng, Hui Su, Xu Zhao, Weiren Cheng, Qinghua Liu, Hongzhen Lin, Jun Luo, Jun Chen, Mingdong Dong, Kai Cheng, Conggang Li, Shuangyin Wang

Australian Institute for Innovative Materials - Papers

© 2020, The Author(s), under exclusive licence to Springer Nature Limited. The use of nitrogen fertilizers has been estimated to have supported 27% of the world’s population over the past century. Urea (CO(NH2)2) is conventionally synthesized through two consecutive industrial processes, N2 + H2 → NH3 followed by NH3 + CO2 → urea. Both reactions operate under harsh conditions and consume more than 2% of the world’s energy. Urea synthesis consumes approximately 80% of the NH3 produced globally. Here we directly coupled N2 and CO2 in H2O to produce urea under ambient conditions. The process was carried out using an …

Predicting Power-Transformer Bushings’ Seismic Vulnerability: Mounting Stiffness And Coupling, Jon Bender, Arvin Farid

Civil Engineering Faculty Publications and Presentations

Large power transformers are both expensive and vulnerable to seismic failure. Excessive amplification of earthquake loading to power transformer bushings beyond the bushings’ rated strength can occur if the system’s structural dynamics produce unpredictable and unfavorable resonance behavior. Determining the degree of vulnerability to large seismic amplifications is not straight-forward, and general design recommendations do not always resolve problems that can potentially arise. This paper considers a number of Case studies in an attempt to postulate a set of critical factors, which might facilitate better prediction of bushing amplification. Further, several additional Case studies are summarized in order to add …

Coupling Topological Insulator Snsb2te4 Nanodots With Highly Doped Graphene For High-Rate Energy Storage, Zhibin Wu, Gemeng Liang, Wei Kong Pang, Tengfei Zhou, Zhenxiang Cheng, Wenchao Zhang, Ye Liu, Bernt Johannessen, Zaiping Guo

Australian Institute for Innovative Materials - Papers

Topological insulators have spurred worldwide interest, but their advantageous properties have scarcely been explored in terms of electrochemical energy storage, and their high-rate capability and long-term cycling stability still remain a significant challenge to harvest. p-Type topological insulator SnSb2Te4 nanodots anchoring on few-layered graphene (SnSb2Te4/G) are synthesized as a stable anode for high-rate lithium-ion batteries and potassium-ion batteries through a ball-milling method. These SnSb2Te4/G composite electrodes show ultralong cycle lifespan (478 mAh g−1 at 1 A g−1 after 1000 cycles) and excellent rate capability (remaining 373 mAh g−1 even at 10 A g−1) in Li-ion storage owing to the rapid …

Magnetoelectric Coupling In Nanoscale 0-1 Connectivity, Yan Zong, Zhilian Yue, Pedro M. Martins, Jincheng Zhuang, Yi Du, Senentxu Lanceros-Mendez, Michael J. Higgins

Australian Institute for Innovative Materials - Papers

The strain-mediated magnetoelectric (ME) coupling between piezoelectric (PE) and magnetostrictive (MS) components are established in various connectivities. Discovering new ME connectivity and elucidating the key factors governing the performance of ME composite are of critical importance to find advanced materials for modern electronics. Reported here is a novel ME coupling in 0-1 connectivity. The unique self-assembling ability of 1-dimension crystalline nanocellulose (CNC) nanowhiskers enables the establishment of ME coupling with 0-dimension cobalt ferrite (CFO) nanoparticles without the use of binder. The developed CFO/CNC 0-1 ME composites display a significant ME voltage coefficient (αME) as high as 0.135 mV cm−1 Oe−1. …

Electromagnetic Design Of A Superconducting Twin Axis Cavity, S. U. De Silva, H. Park, J. R. Delayen, F. Marhauser, A. Hutton

Physics Faculty Publications

The twin-axis cavity is a new kind of rf superconducting cavity that consists of two parallel beam pipes, which can accelerate or decelerate two spatially separated beams in the same cavity. This configuration is particularly effective for high-current beams with low-energy electrons that will be used for bunched beam cooling of high-energy protons or ions. The new cavity geometry was designed to create a uniform accelerating or decelerating fields for both beams by utilizing a TM₁₁₀ dipole mode. This paper presents the design rf optimization of a 1497 MHz twin-axis single-cell cavity, which is currently under fabrication.

Coupling A Thermal Comfort Model With Building Simulation For User Comfort And Energy Efficiency, Katharina Boudier, Massimo Fiorentini, Sabine Hoffmann, Raghuram Kalyanam, Georgios Kokogiannakis

Faculty of Engineering and Information Sciences - Papers: Part B

This paper describes a methodology for coupling an advanced model of the thermo-regulatory system of the human body that describes its physiological processes, a comfort model that evaluates thermal sensation and comfort, and the ESP-r building simulation software that computes the transient thermal response of a building model. The objective of this study was to utilise the physiology and comfort models to dynamically modify the heating and cooling temperature set points of a zone controller in ESP-r, in accordance with the computed human thermal sensation and achieve realtime thermal comfort management. The comunication between the software is managed by the …

Manipulating Coupling State And Magnetism Of Mn-Doped Zno Nanocrystals By Changing The Coordination Environment Of Mn Via Hydrogen Annealing, Yan Cheng, W Li, Weichang Hao, Huaizhe Xu, Zhongfei Xu, Li Rong Zheng, Jing Zhang, S X. Dou, Tianmin Wang

Australian Institute for Innovative Materials - Papers

Mn-doped ZnO nanocrystals are synthesized by a wet chemical route and treated in H2/Ar atmosphere with different H2/Ar ratios. It is found that hydrogen annealing could change the coordination environment of Mn in ZnO lattice and manipulate the magnetic properties of Mn-doped ZnO. Mn ions initially enter into interstitial sites and a Mn3+O6 octahedral coordination is produced in the prepared Mn-doped ZnO sample, in which the nearest neighbor Mn3+ and O2 ions could form a Mn3+-O2--Mn3+ complex. After H2 annealing, interstitial Mn ions can substitute for Zn to generate the Mn2+O4 tetrahedral coordination in the nanocrystals, in which neighboring Mn2+ …

Interface-Enhanced Electron-Phonon Coupling And High-Temperature Superconductivity In Potassium-Coated Ultrathin Fese Films On Srtio3, Chenjia Tang, Chong Liu, Guanyu Zhou, Fangsen Li, Hao Ding, Zhi Li, Ding Zhang, Zheng Li, Canli Song, Shuaihua Ji, Ke He, Lili Wang, Xucan Ma, Qi-Kun Xue

Australian Institute for Innovative Materials - Papers

Alkali-metal (potassium) adsorption on FeSe thin films with thickness from 2 unit cells (UC) to 4 UC on SrTiO3 grown by molecular beam epitaxy is investigated with a low-temperature scanning tunneling microscope. At appropriate potassium coverage (0.20-0.25 monolayer), the tunneling spectra of the films all exhibit a superconductinglike gap which is overall larger than 11 meV (five times the gap value of bulk FeSe) and decreases with increasing thickness, and two distinct features of characteristic phonon modes at ∼11 and ∼21 meV. The results reveal the critical role of the interface-enhanced electron-phonon coupling for possible high-temperature superconductivity in ultrathin FeSe …

Magnetocaloric Effect And Magnetostructural Coupling In Mn0.92fe0.08coge Compound, Jianli Wang, Precious Shamba, Wayne D. Hutchison, Qinfen Gu, M F. Md Din, Q Y. Ren, Zhenxiang Cheng, Shane J. Kennedy, Stewart J. Campbell, S X. Dou

Australian Institute for Innovative Materials - Papers

The structural properties of Mn_0.92Fe_0.08CoGe have been investigated in detail using synchrotron x-ray diffraction in zero and applied pressure (p = 0-10 GPa). A ferromagnetic transition occurs around T_C = 300 K and a large magnetic-entropy change −ΔS_M = 17.3 J/kg K detected at T_C for a field change of ΔB = 5 T. The field dependence of −ΔS _M ^max can be expressed as −ΔS _M ^max ∝ B. At ambient temperature and pressure, Mn_0.92Fe_0.08CoGe exhibits a co-existence of the orthorhombic TiNiSi-type structure (space group Pnma) and hexagonal …

Voltage Sag Compensation Of Point Of Common Coupling For Low Voltage Ride-Through Enhancment Of Inverter Interfaced Dg Using Bridge Type Fcl, Seyed Behzad Naderi, Michael Negnevitsky, Amin Jalilian, Mehrdad Tarafdar Hagh, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

Fully converter wind turbines and solar power utilise an inverter to connect to grid. The inverters are vulnerable to voltage sag in their terminal due to its damaging effect on semiconductor self-Turnoff switches. In this paper, a bridge-Type fault current limiter (B-FCL) is proposed for low voltage ride-Through (LVRT) of the inverters during different types of fault with simple control system. The proposed B-FCL is capable to compensate the voltage sag in point of common coupling (PCC) and makes a safe condition not only for the inverter but also for any equipment which has been connected to the PCC in …

Field Penetration In Mri-Based Breast Models: A Numerical Investigation, Giuseppe Ruvio, Raffaele Solimene, Antonio Cuccaro, Max Ammann

Articles

The use of reliable computational tools is fundamental to investigate different aspects of microwave breast cancer imaging. From the development of high-definition and realistic numerical breast models, different coupling mechanisms and the reaction of different tissues to microwave signals can be characterized. In this paper, field penetration inside four numerical breast phantoms with varying adipose content is evaluated in the frequency range 0.5 - 10 GHz across sagittal cuts.

Nonlinear Optical Conductivity Of Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling In Terahertz Regime, Yee Sin Ang, J C. Cao, Chao Zhang

Australian Institute for Innovative Materials - Papers

We reveal that two-dimensional semiconductors with Rashba spin-orbit interaction (R2DG) exhibit exceptionally strong nonlinear optical response (NOR) in the terahertz frequency regime. The spin-split of the parabolic energy band in R2DG allows strong multiple-photon process to occur via inter-subband mechanism. We show sharp multiple photon edges in the nonlinear conductivity. The edges correspond to the cut-off effect produced by the multiple-photon process. For Rashba coupling parameter of λ R ≈ 10−10 eV m, electric field strength in the order of only 102 V/cm is required for the NOR to dominate over the linear response. Furthermore, the roles of the parabolic …

Large Magnetoelectric Coupling In Magnetically Short-Range Ordered Bi5ti3feo15 Film, Hongyang Zhao, Hideo Kimura, Zhenxiang Cheng, Minoru Osada, Jianli Wang, Xiaolin Wang, S X. Dou, Yan Liu, Jianding Yu, Takao Matsumoto, Tetsuya Tohei, Naoya Shibata, Yuichi Ikuhara

Australian Institute for Innovative Materials - Papers

Multiferroic materials, which offer the possibility of manipulating the magnetic state by an electric field or vice versa, are of great current interest. However, single-phase materials with such cross-coupling properties at room temperature exist rarely in nature; new design of nano-engineered thin films with a strong magneto-electric coupling is a fundamental challenge. Here we demonstrate a robust room-temperature magneto-electric coupling in a bismuth-layer-structured ferroelectric Bi5Ti3FeO15 with high ferroelectric Curie temperature of ~1000 K. Bi5Ti3FeO15 thin films grown by pulsed laser deposition are single-phase layered perovskit with nearly (00l)-orientation. Room-temperature multiferroic behavior is demonstrated by a large modulation in magneto-polarization and …

Chiral-Like Tunneling Of Electrons In Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling, Yee Sin Ang, Zhongshui Ma, C Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

The unusual tunneling effects of massless chiral fermions (mCF) and massive chiral fermions (MCF) in a single layer graphene and bilayer graphene represent some of the most bizarre quantum transport phenomena in condensed matter system. Here we show that in a two-dimensional semiconductor with Rashba spin-orbit coupling (R2DEG), the real-spin chiral-like tunneling of electrons at normal incidence simultaneously exhibits features of mCF and MCF. The parabolic branch of opposite spin in R2DEG crosses at a Dirac-like point and has a band turning point. These features generate transport properties not found in usual two-dimensional electron gas. Albeit its p Berry phase, …

Raman Scattering Reveals Strong Lo-Phonon-Hole-Plasmon Coupling In Nominally Undoped Gaasbi: Optical Determination Of Carrier Concentration, Julian Steele, R A. Lewis, M Henini, O M. Lemine, D. Fan, Yu. I. Mazur, V G. Dorogan, P C. Grant, S Q. Yu, G J. Salamo

Faculty of Engineering and Information Sciences - Papers: Part A

We report room-temperature Raman scattering studies of nominally undoped (100) GaAs1−xBix epitaxial layers exhibiting Bi-induced (p-type) longitudinal-optical-plasmon-coupled (LOPC) modes for 0.018 ≤ x ≤ 0.048. Redshifts in the GaAs-like optical modes due to alloying are evaluated and are paralleled by strong damping of the LOPC. The relative integrated Raman intensities of LO(Γ) and LOPC ALO/ALOPC are characteristic of heavily doped p-GaAs, with a remarkable near total screening of the LO(Γ) phonon (ALO/ALOPC → 0) for larger Bi concentrations. A method of spectral analysis is set out which yields estimates of hole concentrations in excess of 5 × 1017cm−3 and correlates …

90° Magnetic Coupling In A Nife/Femn/Biased Nife Multilayer Spin Valve Component Investigated By Polarized Neutron Reflectometry, S J. Callori, J Bertinshaw, David L. Cortie, J W. Cai, A P. Le Brun, T Zhu, Frank Klose

Australian Institute for Innovative Materials - Papers

We have observed 90° magnetic coupling in a NiFe/FeMn/biased NiFe multilayer system using polarized neutron reflectometry. Magnetometry results show magnetic switching for both the biased and free NiFe layers, the latter of which reverses at low applied fields. As these measurements are only capable of providing information about the total magnetization within a sample, polarized neutron reflectometry was used to investigate the reversal behavior of the NiFe layers individually. Both the non-spin-flip and spin-flip neutron reflectometry signals were tracked around the free NiFe layer hysteresis loop and were used to detail the evolution of the magnetization during reversal. At low …

Electronic Coupling And Catalytic Effect On H2 Evolution Of Mos2/Graphene Nanocatalyst, Ting Liao, Ziqi Sun, Chenghua Sun, S X. Dou, Debra J. Searles

Australian Institute for Innovative Materials - Papers

Inorganic nano-graphene hybrid materials that are strongly coupled via chemical bonding usually present superior electrochemical performance. However, how the chemical bond forms and the synergistic catalytic mechanism remain fundamental questions. In this study, the chemical bonding of the MoS 2 nanolayer supported on vacancy mediated graphene and the hydrogen evolution reaction of this nanocatalyst system were investigated. An obvious reduction of the metallic state of the MoS 2 nanolayer is noticed as electrons are transferred to form a strong contact with the reduced graphene support. The missing metallic state associated with the unsaturated atoms at the peripheral sites in turn …

Imaging The Electron-Boson Coupling In Superconducting Fese Films Using A Scanning Tunneling Microscope, Canli Song, Yi-Lin Wang, Yeping Jiang, Zhi Li, Lili Wang, Ke He, Xi Chen, Jennifer E. Hoffman, Xu-Cun Ma, Qi-Kun Xue

Australian Institute for Innovative Materials - Papers

Scanning tunneling spectroscopy has been used to reveal signatures of a bosonic mode in the local quasiparticle density of states of superconducting FeSe films. The mode appears below Tc as a "dip-hump" feature at energy Ω ∼ 4.7kBTc beyond the superconducting gap Δ. Spectra on strained regions of the FeSe films reveal simultaneous decreases in Δ and Ω. This contrasts with all previous reports on other high-Tc superconductors, where Δ locally anticorrelates with Ω. A local strong coupling model is found to reconcile the discrepancy well, and to provide a unified picture of the electron-boson coupling in unconventional superconductors.

Advances In The Redcat Software Package, Chris Schmidt, Stephanie J. Irausquin, Homayoun Valafar

Faculty Publications

Background

Residual Dipolar Couplings (RDCs) have emerged in the past two decades as an informative source of experimental restraints for the study of structure and dynamics of biological macromolecules and complexes. The REDCAT software package was previously introduced for the analysis of molecular structures using RDC data. Here we report additional features that have been included in this software package in order to expand the scope of its analyses. We first discuss the features that enhance REDCATs user-friendly nature, such as the integration of a number of analyses into one single operation and enabling convenient examination of a structural ensemble …

Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou

Faculty of Engineering and Information Sciences - Papers: Part A

Electron-phonon coupling strength was studied in graphene-MgB2 composites to explore the possibilities for a higher superconducting transition temperature (Tc). For the first time in the experimental work on MgB2, the Raman active E2g mode was split into two parts: a softened mode corresponding to tensile strain and a hardened mode attributed to the carbon substitution effect. The tensile strain effect is suggested to improve Tc of graphene-MgB2 composites because it increases the electron-phonon coupling strength of MgB2.