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Q-switched pulse generation from an all-f iber distributed Bragg reflector laser using graphene as saturable absorber

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Chinese Optics Letters 2013年第7期11卷 46-49页

作者： H. Ahmad f. d. muhammad M. Z. Zulkifli S. W. Harun Photonics Research Centre Department of Physics University of Malaya Nanotechnology Research Alliance Universiti Teknologi Malaysia

A Q-switched distributed Bragg reflector fiber laser using a graphene passive saturable absorber is proposed in a cavity consisting of a fiber Bragg grating and faraday rotator mirror as end mirrors, together with a highly doped erbium-doped fiber as a gain source. The laser has a Q-switched threshold of about 28 mW and a tunable repetition rate of 10.4-18.0 kHz with varying pump power. The shortest pulse width obtained from the system is 3.7 its, with a maximum pulse energy and peak power of 22.2 nJ and 3.4 mW, respectively.

关键词： dBR Q-switched pulse generation from an all-f iber distributed Bragg reflector laser using graphene as saturable absorber Edf kHz dBm figure

Thermal Stability and Effect of Heat Treatment on Manganese doped Silica Borotellurite Glass

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Journal of Materials Science and Chemical Engineering 2018年第4期6卷 24-30页

作者： I. Zaitizila M. K. Halimah f. d. muhammad M. f. faznny Glass and dielectric Lab Department of Physics Faculty of Science University Putra Malaysia Serdang Malaysia

Glasses with chemical formula of {[(TeO2)0.7(B2O3)0.3]0.8[SiO2]0.2}1-x{MnO2}x where x = 0.00 ≤ x ≤ 0.05 molar fraction were fabricated using melt quenching technique. The temperature used in the heat treatment process of the glass sample is 600?C. Calorimetric measurement had been carried out to study the thermal properties of the fabricated glass. The crystallization kinetics of the glass system we reexamined under non-isothermal conditions via differential scanning calorimetric (dSC). The glass transition (Tg), onset glass transition (To), maximum crystallization temperature (Tc) and melting temperature (Tm) were determined. Results from dSC proved that the studied glasses have good thermal stability (Ts) in which indicates its high resistance to devitrification. Strong indicator for the glass forming ability of a glass material, Hurby parameter (Kgl) was also calculated in this research.

关键词： Manganese Thermal Stability dSC Heat Treatment

Analysis of b→cτν¯_(τ)anomalies using weak effective Hamiltonian with complex couplings and their impact on various physical observables

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Chinese Physics C 2024年第8期48卷 56-75页

作者： muhammad Arslan Tahira Yasmeen Saba Shafaq Ishtiaq Ahmed muhammad Jamil Aslam department of Physics Quaid-i-Azam UniversityIslamabad 45320Pakistan department of Physics International Islamic UniversityIslamabad 44000Pakistan National Center for Physics Islamabad 44000Pakistan

Recently,the experimental measurements of the branching ratios and different polarization asymmetries for processes occurring through flavor-changing-charged current(b→cτν¯_(τ))transitions by BABAR,Belle,and LHCb have revealed some significant differences from the corresponding Standard Model(SM)*** has triggered an interest to search for physics beyond the SM in the context of various new physics(NP)models and using the model-independent weak effective Hamiltonian(WEH).Assuming left-handed neutrinos,we add the dimension-six vector,(pseudo-)scalar,and tensor operators with complex Wilson coefficients(WCs)to the SM *** 60%,30%,and 10%constraints resulting from the branching ratio of B_(c)→τν¯_(τ),we reassess the parametric space of these new physics WCs accommodating the current anomalies based on the most recent HfLAV data of R_(τ/μ,e)(d)and R_(τ/μ,e)(d^(*))and Belle data of f_(L)(d^(*))and P_(τ)(d^(*)).We find that the allowed parametric region of left-handed scalar couplings strongly depends on the constraints of the B_(c)→τν¯_(τ)branching ratio,and the maximum pull from the SM predictions results from theficantly if we extend the analysis by adding LHCb data of R_(τ/μ)(J/ψ)and R_(τ/ℓ)(Λ_(c)).furthermore,due to the large uncertainties in the measurements of R_(τ/μ)(J/ψ)and R_(τ/ℓ)(X_(c)),we derive the sum rules which complement them with R_(τ/μ,e)(d)and R_(τ/μ,e)(d^(*)).Using the best-fit points of the new complex WCs along with the latest measurements of R_(τ/μ,e)(d(^(*))),we predict the numerical values of the observable R_(τ/ℓ)(Λ_(c)),R_(τ/μ)(J/ψ),and R_(τ/ℓ)(X_(c))from the sum *** simultaneous dependence of abovementioned physical observables on the NP WCs is established by plotting their correlation with R_(d) and R_(d^(*)),which are useful to discriminate between various NP *** find that the most significant impact of NP results from the WC C^(S)_(L)=4C^(T).fi

关键词： B meson anomalies new physics complex coupling HfLAV

Circulating tumor dNA and its role in detection, prognosis and therapeutics of hepatocellular carcinoma

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Chinese Journal of Cancer Research 2024年第2期36卷 195-214页

作者： Sana Rashid Yingchuan Sun Umair Ali Khan Saddozai Sikandar Hayyat muhammad Usman Munir muhammad Usman Akbar muhammad Babar Khawar Zhiguang Ren Xinying Ji Malik Ihsan Ullah Khan Institute of Molecular Biology and Biotechnology University of LahoreLahore 54590Pakistan department of Internal Oncology(Section Ⅰ) Xuchang Municipal Central HospitalXuchang 461000China Institute of Translational Medicine Medical CollegeYangzhou UniversityYangzhou 225001China Australian Institute for Bioengineering&Nanotechnology the University of QueenslandBrisbane 4072Australia Gomal Center of Biochemistry and Biotechnology Gomal UniversityDera Ismail Khan 29111Pakistan Applied Molecular Biology and Biomedicine Lab Department of ZoologyUniversity of NarowalNarowal Punjab 51600Pakistan Kaifeng Municipal Key Laboratory for Infection and Biosafety Henan International Joint Laboratory of Nuclear Protein RegulationSchool of Basic Medical SciencesHenan UniversityKaifeng 475004China faculty of Basic Medical Subjects Shu-Qing Medical College of ZhengzhouZhengzhou 450064China department of Medicine Huaxian County People's HospitalHuaxian 456400China

Hepatocellular carcinoma(HCC) is considered the fifth most prevalent cancer among all types of cancers and has the third most morbidity value. It has the most frequent duplication time and a high recurrence rate. Recently, the most unique technique used is liquid biopsies, which carry many markers;the most prominent is circulating tumor dNA(ctdNA). Varied methods are used to investigate ctdNA, including various forms of polymerase chain reaction(PCR) [emulsion PCR(ePCR), digital PCR(dPCR), and bead, emulsion, amplification, magnetic(BEAMing) PCR]. Hence ctdNA is being recognized as a potential biomarker that permits early cancer detection,treatment monitoring, and predictive data on tumor burden are subjective to therapy or surgery. Numerous ctdNA biomarkers have been investigated based on their alterations such as 1) single nucleotide variations(either insertion or deletion of a nucleotide) markers including TP53, KRAS, and CCNd1;2) copy number variations which include markers such as CdK6, EfGR, MYC and BRAf;3) dNA methylation(RASSf1A, SEPT9, KMT2C and CCNA2);4) homozygous mutation includes ctdNA markers as CdKN2A, AXIN1;and 5) gain or loss of function of the genes, particularly for HCC. Various researchers have conducted many studies and gotten fruitful ***, there are some drawbacks to ctdNA namely low quantity, fragment heterogeneity, less stability, limited mutant copies and standards, and differential sensitivity. However, plenty of investigations demonstrate ctdNA's significance as a polyvalent biomarker for cancer and can be viewed as a future diagnostic, prognostic and therapeutic agent. This article overviews many conditions in genetic changes linked to the onset and development of HCC, such as dysregulated signaling pathways, somatic mutations, single-nucleotide polymorphisms, and genomic instability. Additionally, efforts are also made to develop treatments for HCC that are molecularly targeted and to unravel some of the genetic pathways that f

关键词： Hepatocellular carcinoma circulating tumor dNA biomarkers single nucleotide variations diagnosis prognosis

Vision based intelligent traffic light management system using faster R‐CNN

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 932-947页

作者： Syed Konain Abbas muhammad Usman Ghani Khan Jia Zhu Raheem Sarwar Naif R.Aljohani Ibrahim A.Hameed muhammad Umair Hassan department of Computer Science and Engineering University of Engineering and TechnologyLahorePakistan Zhejiang Key Laboratory of Intelligent Education Technology and Application Zhejiang Normal UniversityJinhuaChina OTHEM Manchester Metropolitan UniversityManchesterUK faculty of Computing and Information Technology King Abdulaziz UniversityJeddahSaudi Arabia department of ICT and Natural Sciences Norwegian University of Science and Technology(NTNU)ÅlesundNorway

Transportation systems primarily depend on vehicular flow on roads. developed coun-tries have shifted towards automated signal control, which manages and updates signal synchronisation automatically. In contrast, traffic in underdeveloped countries is mainly governed by manual traffic light systems. These existing manual systems lead to numerous issues, wasting substantial resources such as time, energy, and fuel, as they cannot make real‐time decisions. In this work, we propose an algorithm to determine traffic signal durations based on real‐time vehicle density, obtained from live closed circuit television camera feeds adjacent to traffic signals. The algorithm automates the traffic light system, making decisions based on vehicle density and employing faster R‐CNN for vehicle detection. Additionally, we have created a local dataset from live streams of Punjab Safe City cameras in collaboration with the local police authority. The proposed algorithm achieves a class accuracy of 96.6% and a vehicle detection accuracy of 95.7%. Across both day and night modes, our proposed method maintains an average precision, recall, f1 score, and vehicle detection accuracy of 0.94, 0.98, 0.96 and 0.95, respectively. Our proposed work surpasses all evaluation metrics compared to state‐of‐the‐art methodologies.

关键词： access control artificial intelligence computer vision intelligent control

Converting TREx-RGB green-channel data to 557.7 nm auroral intensity:Methodology and initial results

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Earth and Planetary Physics 2024年第1期8卷 258-274页

作者： Jun Liang d.M.Gillies E.Spanswick E.f.donovan University of Calgary CalgaryT2N 1N4Canada

The recently deployed Transition Region Explorer(TREx)-RGB(red-green-blue)all-sky imager(ASI)is designed to capture“true color”images of the aurora and *** the 557.7 nm green line is usually the brightest emission line in visible auroras,the green channel of a TREx-RGB camera is usually dominated by the 557.7 nm *** this rationale,the TREx mission does not include a specific 557.7 nm imager and is designed to use the RGB green-channel data as a proxy for the 557.7 nm *** this study,we present an initial effort to establish the conversion ratio or formula linking the RGB green-channel data to the absolute intensity of 557.7 nm auroras,which is crucial for quantitative uses of the RGB *** illustrate two approaches:(1)through a comparison with the collocated measurement of green-line auroras from the TREx spectrograph,and(2)through a comparison with the modeled green-line intensity according to realistic electron precipitation flux measurements from low-Earth-orbit satellites,with the aid of an auroral transport *** demonstrate the procedures and provide initial results for the TREx-RGB ASIs at the Rabbit Lake and Lucky Lake *** RGB response is found to be *** conversion ratios or formulas between RGB green-channel data and the green-line auroral intensity are given and can be applied immediately by TREx-RGB data *** methodology established in this study will also be applicable to the upcoming SMILE ASI mission,which will adopt a similar RGB camera system in its deployment.

关键词： TREx RGB green-line aurora auroral transport model

The magnetosheath at high spectral resolution

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Earth and Planetary Physics 2024年第1期8卷 234-246页

作者： K.d.Küntz d.Koutroumpa W.R.dunn A.foster f.S.Porter d.G.Sibeck B.Walsh The Henry A.Rowland department of Physics and Astronomy Johns Hopkins University3701 San Martin DriveBaltimoreMD21218USA NASA Goddard Space flight Center 8800 Greenbelt RoadGreenbeltMD 20771USA LATMOS-OVSQ CNRSUVSQ Paris-SaclaySorbonne Université11 Boulevard d’Alembert78280GuyancourtFrance department of Physics and Astronomy University College LondonLondonUK The Centre for Planetary Science at UCL/Birkbeck Gower StreetLondon WC1E 6BTUK Center for Astrophysics Harvard University&Smithsonian Institution60 Garden StreetCambridgeMA 02138USA Center for Space Physics Boston University110 Cummington MallBostonMAUSA

While we eagerly anticipate SMILE’s(Solar wind Magnetosphere Ionosphere Link Explorer)unprecedented X-ray observations of the Earth’s magnetosheath and the initiation of a new era of magnetospheric research,it seems appropriate to look ahead to the abilities of the next generation of astrophysics *** these,the Line Emission Mapper(LEM),a large aperture micro-calorimeter based mission,is currently planned to be able to observe the magnetosheath at high spectral resolution(~2 eV).With a field of view of~30′,LEM will allow higher spatial resolution and higher cadence measurement of the motion of a very small portion of the magnetopause over relatively short periods of time(multiple hours),complementing SMILE’s global ***’s strength is its spectral *** will be able to measure the abundance of a broad range of elements and ionization states,many of which are inaccessible to current in situ instruments,and will be able to separate the emission from the magnetosheath from the emission from the cosmic X-ray background using the difference in their relative velocities.

关键词： magnetosheath charge exchange solar wind abundances

Highly responsive broadband Si-based MoS2 phototransistor on high-k dielectric

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Science China(Information Sciences) 2024年第6期67卷 180-189页

作者： Ali IMRAN Xin HE Jiwei LIU Qinghai ZHU muhammad SULAMAN fei XUE Mingsheng XU deren YANG College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University ZJU-Hangzhou Global Scientific and Technological Innovation Centre School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of Technology

The demand for photodetectors and image sensors has grown exponentially in the past decade in biomedical, security surveillance, robotics, automotive, quality control, image recognition, and military applications, due to their superior quality, broadband detection, lower noise, and economic viability. Here,we report a MoS2channel-based phototransistor over an HfO2/n-Si substrate isolated by an h BN layer. The high photoresponse is achieved through the integration of the photoconduction, photogating, and mobility enhancement process by utilizing excellent features of MoS2, HfO2/Si, and h BN. The capacitive coupling of the photogenerated carriers by high-k dielectric HfO2leads to modulation of MoS2fermi level due to electrostatic doping. furthermore, the MoS2also contributes to the photogeneration of carriers due to its semiconducting nature, leading to additional photocurrent. Ultimately, the combination of photogating,photoconduction, and swift carrier extraction with remarkable mobility of 11.65 cm2· V-1· s-1results in high responsivity, external quantum efficiency, and detectivity of 4.5 × 10～8A · W-1, 0.72 × 10～6, and 6.20× 1016Jones at 266 nm illumination, respectively. The device also demonstrates broadband photoresponse from 266–1000 nm wavelengths. The high responsivity distinguishes the potential of our device for the future of optoelectronics and broadband image sensing applications.

关键词： photogating photoconduction two-dimensional materials high k dielectric carrier scattering phototransistor

facile synthesis of graphene anchored rare earth doped mixed metal ferrite nanorods:A potential candidate for azo dye mineralization

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Journal of Rare Earths 2024年第5期42卷 907-916,I0004页

作者： Tehmina Kousar muhammad Aadil Sonia Zulfiqar Sobhy MIbrahim Sidra Mubeen Warda Hassan Kashuf Shafiq farzana Mahmood Institute of Chemical Sciences Bahauddin Zakariya UniversityMultan60800Pakistan department of Chemistry Rahim Yar Khan CampusThe Islarnia University of BahawalpurRahim Yar Khan64200Pakistan department of Chemistry Faculty of ScienceUniversity of Ostrava30.Dubna 22Ostrava70103Czech Republic department of Chemical and Biological Engineering Iowa State UniversitySweeney Hall618 Bissell RoadAmeslowa50011United States department of Biochemistry College of ScienceKing Saud UniversityPO.Box 2455Riyadh11451Saudi Arabi department of Chemistry The Women University Multan66000Pakistan

Bandgap tuning using rare earth metals as dopants in ferrite-based photocatalytic materials has received a lot of interest because the fermi 4f energy of these metals generates a sub-energy state in the bandgap generated by the overlapping of fe-3d and O-2p ***,dysprosium-doped cobalt-nickel mixed ferrite(d-CNfO)and its graphene-reinforced composite(d-CNfO@G)were prepared and an ideal photocatalyst material for azo dye mineralization was proposed.A cost-effective combination of wetchemical and ultrasonication methods was used to prepare the doped and composite *** characterization methodologies were used to scrutinize the optical,compositional,structural,morphological,and photocatalytic characteristics of as-prepared *** X-ray diffraction analysis identified the spinel phase's(cubic)structure,while the electronic spectroscopy examination confirmed the prepared samples'rod-like *** UV/visible absorbance spectrum shows the higher light harvesting behavior of the d-CNfO@G in the visible *** mineralization performance of the dCNfO and d-CNfO@G composites was analyzed using Congo-red(an anionic dye),a well-known azo *** d-CNfO@G sample removes Congo-red dye at a rate almost 2.4%faster than the d-CNfO *** experiment involving trapping free radicals indicates that hydroxyl radical play s a crucial role in dye *** the d-CNfO@G catalyst is magnetic and can be isolated easily from the photocatalytic system,it shows an awkward cycle activity of more than 96%after five mineralization *** asprepared d-CNfO@G composite is proved as an excellent option for azo dye mineralization because of the combined impacts of rare earth doping,graphene reinforcement and nanotechnology.

关键词： azo-dye Composite Graphene dy-doped Nanotechnology Rare earths