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A Comprehensive Classification and Analysis of Geomagnetic Storms Over Solar Cycle 24

Research in Astronomy and Astrophysics 2024年第8期24卷 77-86页

作者： Raja Adibah Raja Halim Shah Nurul Shazana Abdul Hamid Mardina Abdullah adlyka annuar Idahwati Sarudin Zahira Mohd Radzi Akimasa Yoshikawa Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia Space Science Centre (ANGKASA) Institute of Climate ChangeUniversiti Kebangsaan Malaysia Department of Electrical Electronic and Systems EngineeringFaculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia School of Physics Universiti Sains Malaysia Malaysian Space Agency (MYSA) International Research Center for Space and Planetary Environmental Science (i-SPES) Kyushu University

A geomagnetic storm is a global disturbance of Earth?s magnetosphere,occurring as a result of the interaction with magnetic plasma ejected from the *** considerable research,a comprehensive classification of storms for a complete solar cycle has not yet been fully developed,as most previous studies have been limited to specific storm *** study,therefore,attempted to present complete statistics for solar cycle 24,detailing the occurrence of geomagnetic storm events and classifying them by type of intensity (moderate,intense,and severe),type of complete interval (normal or complex),duration of the recovery phase (rapid or long),and the number of steps in the storm?s *** analysis was applied to data from ground-based magnetometers,which measured the Dst index as provided by the World Data Center for Geomagnetism,Kyoto,*** study identified 211 storm events,comprising moderate (177 events),intense (33 events),and severe (1 event) *** 36%of ICMEs and 23%of CIRs are found to be geoeffective,which caused geomagnetic *** to four-step development of geomagnetic storms was exhibited during the main phase for this solar *** showed the geomagnetic storms developed one or more steps in the main phase,which were probably related to the driver that triggered the geomagnetic storms.A case study was additionally conducted to observe the variations of the ionospheric disturbance dynamo (Ddyn) phenomenon that resulted from the geomagnetic storm event of 2015July *** attenuation of the Ddyn in the equatorial region was analyzed using the H component of geomagnetic field data from stations in the Asian sector (Malaysia and India).The variations in the Ddyn signatures were observed at both stations,with the TIR station (India) showing higher intensity than the LKW station (Malaysia).

关键词： (Sun:) solar-terrestrial relations (Sun:) sunspots Sun: activity Sun: coronal mass ejections (CMEs)

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X-ray source population in the polar ring galaxy NGC 660 as observed by Chandra

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Research in Astronomy and Astrophysics 2021年第11期21卷 180-188页

作者： Nurnabilah Nazri adlyka annuar Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia

We present Chandra observations of the nearby polar ring galaxy NGC 660 to study its X-ray source *** on our analysis,we detected a total of 23 X-ray sources in the 0.5-8 keV band,with luminosities ranging from~1037 to~1039 erg ***-two of these sources are located offnuclear and have luminosities below the ultraluminous X-ray source(ULX)threshold value of L0.5-8 keV<1039 erg s-1,suggesting that they are likely to be X-ray binary(XRB)*** remaining source is located at the center of the galaxy,suggesting it is an active galactic nucleus(AGN).However,we estimated that four of the detected sources could be associated with background *** on the source count rates in each of the Chandra observations,we found evidence for variability in nine of the 23 sources,including the ***,further investigation with spectral analysis suggested no significant differences in the AGN luminosities between the *** X-ray luminosity distribution of the galaxy was found to be generally lower than that expected from previous studies on star forming and collisional ring *** ULX was also detected in the galaxy,in contrast with what was expected from the galaxy’s SFR and metallicity(i.e.,SFR=14.43±0.19 M⊙yr-1 and Z=0.94±0.01 Z⊙,respectively).These results suggest a deficit in the X-ray sources *** on source hardness ratio distribution,we found evidence that the fainter sources have a harder source spectrum,indicating higher *** further suggests that there could be more X-ray sources that were not detected in the galaxy due to significant obscuration.

关键词： Galaxies:individual:NGC 660 X-rays:individual:NGC 660 Galaxies:active

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NGC 4117:A New Compton-thick AGN Revealed by Broadband X-Ray Spectral Analysis

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Research in Astronomy and Astrophysics 2023年第5期23卷 19-26页

作者： Pavithra Mohanadas adlyka annuar Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia

In this paper,we present the broadband(0.5–195 keV)X-ray spectral analysis for one of the newly detected AGNs in the Swift-BAT 105 month Hard X-ray Survey Catalog,NGC *** to our ongoing research on low luminosity AGNs from the Swift-BAT 105 month catalog,we examine whether they are indeed low luminosity or heavily obscured *** of the AGNs in our sample is NGC 4117,where we discover it could be potentially a *** to examine NGC 4117 in detail,we combined the high energy Swift-BAT data with low energy data from XMM-Newton and Swift-XRT,and fitted the spectra simultaneously using physically-motivated models.A high absorption occurred at lower energies,i.e.,below 3 *** studies suggested that NGC 4117was heavily obscured with a large column density(~10^(23)cm^(-2)).Our fitting suggests that this AGN is in the Compton-thick regime with a predicted line-of-sight column density(N_(H,los))of 3.82×1024cm^(-2)and a torus column density(N_(H,tor))of 3.07×10^(24)cm^(-2).Both models yield intrinsic luminosity of 1.03×10^(42)erg s^(-1)at 2–10 keV while our bolometric luminosity is 2.05×10^(43)erg s^(-1),indicating that NGC 4117 is not an intrinsically low luminosity ***,it is a standard *** value of Eddington ratio that we obtained is 0.22,suggesting a very high accretion rate for this AGN.

关键词： galaxies active-X-rays galaxies-techniques spectroscopic

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The stellar system HIP 101227:is it a binary,a triple or a quadruple system?

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Research in Astronomy and Astrophysics 2021年第5期21卷 121-129页

作者： Zahra Talal Yousef adlyka annuar Abdallah Mohammad Hussein Hamid Al-Naimiy MashhoorAl-Wardat Nurul Shazana Abdul Hamid Mohammed Fadil Talafha Department of Applied Physics Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorMalaysia Department of Physics Al al-Bayt UniversityMafraq 25113Jordan Department of Applied Physics and Astronomy University of SharjahP.O.Box 27272 SharjahUnited Arab Emirates Sharjah Academy for Astronomy Space Sciences and Technology SAASSTUniversity of SharjahP.O.Box 27272 SharjahUnited Arab Emirates

In this paper,we present the analysis of the stellar system HIP 101227 to determine the actual number of components in the system,and their *** use dynamical modeling and complex spectrophotometric(involving atmospheric modeling)techniques with recent data,to determine the physical properties and orbital solution for the system,respectively,with better accuracy than past *** on our analysis,we found that the system is more consistent with being a quadruple rather than a binary or a triple system as suggested by previous *** total mass of the system determined from our SED analysis is 3.42±0.20 M,which is distributed almost equally between the four *** stars are found to be zero-age main sequence stars;i.e.,at the last stage of pre-main sequence,with age less than 200 Myr and spectral types *** four stars have very similar physical characteristics,suggesting that the fragmentation process is the most likely theory for the formation and evolution of the system.

关键词： stars:binaries:close stars:binaries:visual stars:individual:HIP 101227

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Strain Sensor Based on Embedded Fiber Bragg Grating in Thermoplastic Polyurethane Using the 3D Printing Technology for Improved Sensitivity

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Photonic Sensors 2022年第3期12卷 68-78页

作者： Harith AHMAD Mohamad Ashraff ALIAS Mohammad Faizal ISMAIL Nor Najwa ISMAIL Muhammad Khairol annuar ZAINI Kok Sing LIM Gilberto BRAMBILLA Kenneth T.V.GRATTAN B.MAzizur RAHMAN Photonics Research Centre University of MalayaKuala Lumpur 50603Malaysia Department of Physics Faculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK School of Mathematics Computer Science and EngineeringCity University of LondonLondon EC1V 0HBUK

A new and easy-to-fabricate strain sensor has been developed,based on fiber Bragg grating(FBG)technology embedded into a thermoplastic polyurethane filament using a 3-dimensional(3D)*** advantage of the flexibility and elastic properties of the thermoplastic polyurethane material,the embedding of the FBG provides durable protection with enhanced flexibility and sensitivity,as compared to the use of a bare *** of an evaluation of its performance have shown that the FBG sensors embedded in this way can be applied effectively in the measurement of strain,with an average wavelength responsivity of 0.0135 nm/cm of displacement for tensile strain and -0.0142 nm/cm for compressive strain,both showing a linearity value of up to 99%.Furthermore,such an embedded FBG-based strain sensor has a sensitivity of~1.74 times greater than that of a bare FBG used for strain measurement and is well protected and suitable for in-the-field *** is also observed that the thermoplastic polyurethane based(TPU-based)FBG strain sensor carries a sensitivity value of~2.05 times higher than that of the polylactic acid based(PLA-based)FBG strain sensor proving that TPU material can be made as the material of choice as a“sensing”pad for the FBG.

关键词： Fiber-optic sensors fiber Bragg grating 3D printing technology multiple-point strain measurement

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Electrical Tree Image Segmentation Using Hybrid Multi Scale Line Tracking Algorithm

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Computers, Materials & Continua 2023年第4期75卷 741-760页

作者： Mohd annuar Isa Mohamad Nur Khairul Hafizi Rohani Baharuddin Ismail Mohamad Kamarol Jamil Muzamir Isa Afifah Shuhada Rosmi Mohd Aminudin Jamlos Wan Azani Mustafa Nurulbariah Idris Abdullahi Abubakar Mas’ud Faculty of Electrical Engineering&Technology Universiti Malaysia PerlisPerlisMalaysia School of Electrical and Electronic Engineering Universiti Sains MalaysiaPenangMalaysia Faculty of Electronic Engineering&Technology Universiti Malaysia PerlisPerlisMalaysia Department of Electrical and Electronics Engineering Jubail Industrial CollegeSaudi Arabia

Electrical trees are an aging mechanismmost associated with partial discharge(PD)activities in crosslinked polyethylene(XLPE)insulation of high-voltage(HV)*** of electrical tree structures gained considerable attention from researchers since a deep understanding of the tree morphology is required to develop new insulation ***-dimensional(2D)optical microscopy is primarily used to examine tree structures and propagation shapes with image segmentation ***,since electrical trees can emerge in different shapes such as bush-type or branch-type,treeing images are complicated to segment due to manifestation of convoluted tree branches,leading to a high misclassification rate during ***,this study proposed a new method for segmenting 2D electrical tree images based on the multi-scale line tracking algorithm(MSLTA)by integrating batch processing *** proposed method,h-MSLTA aims to provide accurate segmentation of electrical tree images obtained over a period of tree propagation observation under optical *** initial phase involves XLPE sample preparation and treeing image acquisition under real-time microscopy *** treeing images are then sampled and binarized in *** the next phase,segmentation of tree structures is performed using the h-MSLTA by utilizing batch processing in multiple instances of treeing ***,the comparative investigation has been conducted using standard performance assessment metrics,including accuracy,sensitivity,specificity,Dice coefficient and Matthew’s correlation coefficient(MCC).Based on segmentation performance evaluation against several established segmentation methods,h-MSLTA achieved better results of 95.43%accuracy,97.28%specificity,69.43%sensitivity rate with 23.38%and 24.16%average improvement in Dice coefficient and MCC score respectively over the original *** addition,h-MSLTA produced accurate measurement results of glo

关键词： Image segmentation multi-scale line tracking electrical tree partial discharge high-voltage cable

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Optical Code Generating Device Using 1×N Asymmetric Hollow Waveguide Couplers

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光子学报 2008年第5期37卷 849-854页

作者： Abang annuar EHSAN Sahbudin SHAARI Mohd Kamil ABD. RAHMAN Kee Mohd Rafique KEE ZAINAL ABIDIN Institute of Microengineering and Nanoelectronics Universiti Kebangsaan Malaysia 43600 UKM Bangi Selangor Malaysia Faculty of Applied Science Universiti Teknologi MARA 40450 Shah Alam Selangor Malaysia Kulliyyah of Science International Islamic University Malaysia P. 0 t3oJ＂ 141 25710 Kuantan Pahang Darul Makmur Malaysia)

An optical code generating device for security access system application is presented. The code generating device constructed using asymmetric hollow optical waveguide coupler design provides a unique series of output light intensities which are successively used as an optical code. The design of the waveguide is made using two major components which are asymmetric Y-junction splitter and a linear taper. Waveguiding is done using a hollow waveguide structure. Construction of higher level 1×N hollow waveguide coupler is done utilizing a basic 1×2 asymmetric waveguide coupler design together with a cascaded design scheme. Non-sequential ray tracing of the asymmetric hollow optical waveguide couplers is performed to predict the optical transmission properties of the waveguide. A representation of the code combination that can be generated from the device is obtained using combinatory number theory.

关键词：光代码光子波导耦合器安全接入系统

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Are Islamic incomes relevance to commercial banks in Malaysia？

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Journal of Modern Accounting and Auditing 2010年第2期6卷 26-37页

作者： Cheng Fan Fah annuar Nasir Department of Economics Facnlty of Economics and Management University Pntra Malaysia Selangor 43400Malaysia Department of Accounting and Finance Faculty of Economics and Management University Putra MalaysiaSelangor 43400 Malaysia

A significant price-to-earnings relation is evident in many research findings, which includes study on Malaysia Stock Markets, that the strength, consistency and magnitude of the relation are not as large as those reported in institutionally more developed markets. However, the price adjustment is stronger if price reaction is measured over a long periods, which is consistent to speculative trading. Firm-specific variables such as revenue, firm size and debt-equity have no incremental information content beyond earnings implies that the market monitoring process in an emerging market focuses on earnings only during financial announcement. Therefore, this paper revisited the study on the relevant of accounting earnings by looking at Islamic Income for commercial banks in Malaysia using the earnings response coefficients, which are the earnings-to-share return coefficients that are estimated for sub earnings components by including Islamic banking incomes in the analysis. This paper discovered that though there is a positive effect, the earnings from Islamic banking operation are small. Thus, the total earnings as well as the sub-categories of earnings of banks appear to enter the pricing considerations of investors.

关键词：股票市场市场分析价格投资

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Low Cost Acrylic-Based 1×2 Asymmetric Plastic Optical Fiber Coupler for Optical Code Generating Devices

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Journal of Electronic Science and Technology of China 2010年第1期8卷 60-64页

作者： Abang annuar Ehsan Sahbudin Shaari Mohd Kamil Abd Rahman Institute of Microengineering and Nanoelectronics Universiti Kebangsaan Malaysia(UKM)43600 UKMBangiSelangorMalaysia Faculty of Applied Science Universiti Teknologi MARA(UiTM)40450 Shah AlamSelangorMalaysia

An optical code generating device has been developed based on a 1×2 asymmetric plastic optical fiber （POF） coupler. The code generating device provides a unique series of output power which are successively used as an optical code in a portable optical access-card system. The device utilizing a tap-off ratio （TOFR） technique based on a simple variation of the tap width of an asymmetric Y-branch splitter, allows various ratios of optical power to be generated. The POF coupler has been fabricated using low cost acrylic material and computer numerical control （CNC） machining technique. The simulated and fabricated results show the same linear characteristics between the TOFR and the tap width. The fabricated device enables a variation of the TOFR from 10% up to 50% for a tap width of 500 um to 1 mm.

关键词： Asymmetric coupler plastic opticalfiber optical fiber tap-off ratio.

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Feasibility and accuracy of coronary imaging in elderly patients using the 64-row multi-detector computed tomography: a correlation study with conventional coronary angiography

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Journal of Geriatric Cardiology 2006年第1期3卷 9-14页

作者： Chee Khoon LIEW Sze Piaw CHIN Tiong Kiam ONG Seyfarth Tobias Yean Yip FONG Choon Kiat ANG Houng Bang LIEW Rapaee annuar Kui Hian SIM Deptartment of Cardiology Sarawak General Hospital SarawakMalaysia Siemens Cardiac Solutions Erlangen Germany Universitv Malaysia Sarawak Malaysia

Background Elderly patients generally have higher occurrence of coronary calcification, increased heart rate and difficulty with prolonged breath-holding. The aim of our study was to investigate the feasibility and accuracy of using 64-row multi-detector computed tomography (MDCT) in the assessment of coronary artery stenoses in elderly patients. Methods One hundred and fifty two patients with suspected or known coronary artery disease were divided into 4 groups according to their age (Group A: 40-49 years,n=34; Group B: 50-59 years, n=57; Group C: 60-69 years, n=48; Group D: 70 years and above; n=13). Coronary CT angiography (CTA) using a 64-row MDCT was performed and the findings were compared with that of conventional coronary angiography (CCA).Using axial images, multi-planar reconstructions (MPR) and maximum intensity projections (MIP), coronary segments of lumen diameter = 1.5mm were analyzed for the presence of significant stenosis (= 50% ). Results Percentages of poor image quality from coronary CTA preventing reliable correlations with CCA were 21%, 14%, 19% and 62% in Groups A to D respectively. Patients in Group D had significantly higher calcium scores compared with the other groups (P＜0.001). In patients where CTA images were of acceptable quality, percentages of accurate correlations with CCA were 89.8%, 93.4%, 86.6% and 78.0% for Groups A to D *** were no significant difference in serum creatinine, heart rate and contrast volume between the 4 groups. Conclusions The 64-row MDCT coronary angiography was less accurate and feasible for patients aged 70 years or above due to heavy coronary calcification and inability to perform a satisfactory breath-hold. However, a high diagnostic accuracy with the MDCT is possible in patients aged less than 70 years.

关键词： computed tomography angiography coronary artery disease elderly

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