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Design and Analysis of an OSA-BR MAC Protocol for Cognitive Radio Ad Hoc Networks

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International Journal of Communications, Network and System Sciences 2014年第7期7卷 223-234页

作者： hassan al-mahdi Mohamed Wahed Safa Abd El-Aziz Faculty of Sciences and Arts Al Jouf UniversityAl QuryyatKSA Faculty of Computers and Information Suez Canal UniversityIsmailiaEgypt

Cognitive Radio (CR) is a new communication network paradigm introduced to solve the problems of spectrum scarcity and inefficient spectrum usage. Basically, it allows the Secondary Users (SUs) to utilize the Licensed Channels (LCs) of the Primary Users (PUs) in an opportunistic manner without causing any harmful interference to the PUs. However, there are many challenges associated with cognitive radio networks, such as the CR Medium Access Control (CR-MAC) protocols. An important issue for CR-MAC protocols is to identify whether the spectrum is licensed or unlicensed. In addition, the sudden appearance of the PU is the most important feature of the distributed CR-MAC protocols. In this paper, a multichannel CR-MAC protocol, which reacts efficiently to the appearance of the PUs, is developed. The proposed protocol is named Opportunistic Spectrum Access with backup channel and Buffered data with Resume (OSA-BR). The OSA-BR is an unaided rendezvous, asynchronous, and contention-based MAC protocol. The proposed protocol operates in heterogeneous environment, where the SUs utilize both LCs and unlicensed channel (ULs) and the activities of the Classical Users (CUs) are taken into consideration. In addition, the concept of the backup channel and the buffer with resume are introduced. The simulation results show that OSA-BR accomplishes 35% throughput gain over the SWITCH protocol and 55% over other CR-MAC protocols.

关键词： Rendezvous Cognitive Radio Ad Hoc Analytical Model

Nanosecond pulse and dual-wavelength Q-switched 1.5 μm fiber laser using MAX phase Cr2TialC2 saturable absorber

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Optoelectronics Letters 2025年第1期21卷 7-12页

作者： Ahmed Shakir al-HITI Hiba hassan Department of Electrical Engineering Faculty of Engineering University of Anbar Department of Laser and Optoelectronics Engineering University of Technology-Iraq

We demonstrated a new type of MAX phase material, chromium titanium aluminum carbide（Cr2TialC2） polymer film, to generate a passively Q-switched erbium-doped fiber laser（EDFL）. The film thickness was measured to be around 45 μm, which was fabricated using the embedding method with polyvinyl alcohol（PVA） polymer as hoster. The saturable absorber（SA） film demonstrates a dual-wavelength passively Q-switched EDFL which operates at 1 531 nm and 1 560.19 nm, respectively. The Q-switching pulse duration could be varied from 2.46 μs to 770 ns, while the repetition rate varied from 92.76 kHz to 106.6 kHz with an increasing input pumping range from 154 mW to 300 mW. The maximum output power and pulse energy of 15.05 mW and 141.18 nJ were obtained at the maximum input power of 300 mW, respectively.

关键词： Saturable absorbers

Status and prospects for symmetric organic redox flow batteries

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Journal of Energy Chemistry 2025年第1期100卷 125-143页

作者： Md al Raihan C.Adam Dyker Department of Chemistry University of New Brunswick

As environmental concerns from fossil fuel consumption intensify, large-scale energy storage becomes imperative for the integration of renewable sources like wind, hydro, and solar with the electrical *** flow batteries, particularly those employing organic molecules, are positioned as a key technology for this purpose. This review explores the growing field of symmetric organic redox flow batteries(ORFBs) within this context. Unlike traditional asymmetric designs based on unique active materials for each electrode, symmetric ORFBs involve a single bipolar species for both electrodes. This review highlights the benefits of a symmetric design, and categorizes five distinct classes of organic bipolar molecules used in both aqueous and non-aqueous solvents. By providing a comprehensive overview of their cell cycling and performance characteristics, the strengths and weaknesses of the diverse categories of bipolar molecules are highlighted for both solvent systems, as are opportunities for future development. This should guide new research directions and advance the development of practical symmetric ORFBs.

关键词： Redox flow battery Symmetric battery Organic battery Aqueous electrolyte Non-aqueous electrolyte

MARIE:One-Stage Object Detection Mechanism for Real-Time Identifying of Firearms

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 279-298页

作者： Diana Abi-Nader hassan Harb ali Jaber ali Mansour Christophe Osswald Nour Mostafa Chamseddine Zaki Computer Science Department Faculty of SciencesLebanese UniversityBeirut146404Lebanon College of Engineering and Technology American University of the Middle EastEgaila54200Kuwait Lab-STICC CNRS UMR 6285ENSTA-BretagneBrest29200France

Security and safety remain paramount concerns for both governments and individuals *** today’s context,the frequency of crimes and terrorist attacks is alarmingly increasing,becoming increasingly intolerable to ***,there is a pressing need for swift identification of potential threats to preemptively alert law enforcement and security forces,thereby preventing potential attacks or violent *** advancements in big data analytics and deep learning have significantly enhanced the capabilities of computer vision in object detection,particularly in identifying *** paper introduces a novel automatic firearm detection surveillance system,utilizing a one-stage detection approach named MARIE(Mechanism for Realtime Identification of Firearms).MARIE incorporates the Single Shot Multibox Detector(SSD)model,which has been specifically optimized to balance the speed-accuracy trade-off critical in firearm detection *** SSD model was further refined by integrating MobileNetV2 and InceptionV2 architectures for superior feature extraction *** experimental results demonstrate that this modified SSD configuration provides highly satisfactory performance,surpassing existing methods trained on the same dataset in terms of the critical speedaccuracy *** these innovations,MARIE sets a new standard in surveillance technology,offering a robust solution to enhance public safety effectively.

关键词： Firearm and gun detection single shot multi-box detector deep learning one-stage detector MobileNet inception convolutional neural network

Assessment of liquefaction potential based on shear wave velocity:Strain energy approach

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3733-3745页

作者： Mohammad hassan Baziar mahdi alibolandi School of Civil Engineering Iran University of Science and TechnologyTehran16846-13114Iran

Liquefaction assessment based on strain energy is significantly superior to conventional stress-based *** main purpose of the present study is to investigate the correlation between shear wave velocity and strain energy capacity of silty *** dissipated energy until liquefaction occurs was calculated by analyzing the results of three series of comprehensive cyclic direct simple shear and triaxial tests on Ottawa F65,Nevada,and Firoozkuh sands with varying silt content by weight and relative ***,the shear wave velocity of each series was obtained using bender element or resonant column ***,for the first time,a liquefaction triggering criterion,relating to effective overburden normalized liquefaction capacity energy(WL=s’c)to effective overburden stresscorrected shear wave velocity(eVs1)has been *** accuracy of the proposed criteria was evaluated using in situ *** results confirm the ability of shear wave velocity as a distinguishing parameter for separating liquefied and non-liquefied soils when it is calculated against liquefaction capacity energy(WL=s’c).However,the proposed WL=s’c-Vs1 curve,similar to previously proposed cyclic resistance ratio(CRR)-Vs1 relationships,should be used conservatively for fields vulnerable to liquefaction-induced lateral spreading.

关键词： Liquefaction Strain energy capacity Shear wave velocity Cyclic triaxial test Cyclic direct simple shear test Resonant column test Bender element test

Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice

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Neural Regeneration Research 2025年第8期20卷 2348-2360页

作者： Mohamed Aghyad al Kabbani Christoph Köhler Hans Zempel Institute of Human Genetics Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany Center for Molecular Medicine Cologne(CMMC) University of CologneCologneGermany Center Anatomy Department ⅡMedical FacultyUniversity of CologneCologneGermany

TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the *** is missorted and aggregated in an array of diseases known as *** are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing *** impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule *** therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to *** investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-KO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic *** sum,P301L-TAU results in changes in micr

关键词： human induced pluripotent stem cell microtubules P301L pR5 mice TAU tauopathy tubulin code

Modeling and numerical simulation of electrical and optical characteristics of a quantum dot light-emitting diode based on the hopping mobility model:Influence of quantum dot concentration

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Chinese Physics B 2022年第6期31卷 725-735页

作者： Pezhman Sheykholeslami-Nasab mahdi Davoudi-Darareh Mohammad hassan Yousefi Faculty of Science Malek Ashtar University of TechnologyShahin-ShahrIran

We present a comprehensive numerical framework for the electrical and optical modeling and simulation of hybrid quantum dot light-emitting diodes(QD-LEDs).We propose a model known as hopping mobility to calculate the carrier mobility in the emissive organic layer doped with quantum dots(QDs).To evaluate the ability of this model to describe the electrical characteristics of QD-LEDs,the measured data of a fabricated QD-LED with different concentrations of QDs in the emissive layer were taken,and the corresponding calculations were performed based on the proposed *** simulation results indicate that the hopping mobility model can describe the concentration dependence of the electrical behavior of the ***,based on the continuity equation for singlet and triplet excitons,the exciton density profiles of the devices with different QD concentrations were ***,the corresponding luminance characteristics of the devices were calculated,where the results are in good agreement with the experimental data.

关键词： hybrid quantum dot light-emitting diode(QD-LED) concentration-dependent hopping mobility effective transport model Gaussian band structure

Surface oxidation study of molten Mg–al alloys by oxide/metal/oxide sandwich method

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Journal of Magnesium and alloys 2022年第6期10卷 1704-1717页

作者： Mohammad mahdi Jalilvand hassan Saghafian Mehdi Divandari Mehdi Akbarifar School of Materials Science and Engineering Iran University of Science and TechnologyNarmakTehran ***Iran

The dynamic oxidation of molten Mg–al alloy was investigated via the oxide/metal/oxide(OMO)sandwich *** characteristics of sandwiches were explored using optical microscopy,scanning electron microscopy,X-ray energy dispersive spectroscopy,and X-ray diffraction *** results showed the formation of porous oxide films with varying thicknesses from 0.43 to 16.7 *** the measurements and calculations confirmed the literature findings that the oxidation product consists mainly of MgO and Mg al_(2)O_(4)*** increase in thickness and amount of folds formed on the oxide films implies the significant effect of aluminum in reducing the oxidation resistance of magnesium.

关键词： OMO sandwich Dynamic oxidation Surface film Oxide morphology Thermodynamics Mg–al alloys

Evidence-Based Immunotherapeutic Effects of Herbal Compounds on Humoral Immunity:Ancient and New Approaches

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Chinese Journal of Integrative Medicine 2021年第4期27卷 313-320页

作者： Fatemeh Nejatbakhsh Mohammad ali Zareian mahdi Yaseliani hassan Abolhassani Department of Iranian Traditional Medicine School of Traditional MedicineTehran University of Medical SciencesTehran(14166)Iran Research Center for Immunodeficiencies Pediatrics Center of ExcellenceChildren's Medical CenterTehran University of Medical SciencesTehran(14194)Iran Division of Clinical Immunology Department of Laboratory MedicineKarolinska InstituteKarolinska University Hospital HuddingeStockholm(SE-14186)Sweden

The human immune system represents a dynamic multiscale system with high complexity in *** immunity,as the main branch of adaptive immunity,is characterized by differentiated stages of the Blymphocytes,producing the final product of antibodies that has a diversity of the tuning mechanisms within genetic and epigenetic levels in confrontation with environmental *** because of disturbed humoral immunity are linked with dysregulation of feedback-regulated signaling and the dynamic of immune components that determine the overall *** products,mainly herbal components have a significant role in tailoring the immune system micro-ecosystem which can diversify the adaptive nature of humoral ***,we review the current evidence-based approaches for the impact of medicinal herbs on humoral immunity signaling and antibody production with a focus on immunotherapeutic applications.

关键词： Bcells adaptive immunity antibody immunotherapy medicinal herb