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Efficient Channel Estimation Techniques for MIMO systems with 1-Bit ADC

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China Communications 2020年第5期17卷 50-64页

作者： Hany sHussein shaimaa Hussein Ehab mahmoud Mohamed Electrical Engineering Dept. College of EngineeringKing Khalid UniversityAbha 61411King of Saudi Arabia Electrical Engineering Dept. Faculty of EngineeringAswan UniversityAswan 81542Egypt Electrical Engineering Dept. College of EngineeringPrince Sattam Bin Abdulaziz UniversityWadi Addwasir 11991King of Saudi Arabia

With a low resolution 1-bit ADC on its receiver(RX) side, MIMO with 1-bit ADC took a considerable step in the fulfillment of the hardware complexity constrains of the internet of things(IoT) PHY layer design. However, applying 1-bit ADC at MIMO RX results in severe nonlinear quantization error. By which, almost all received signal amplitude information is completely distorted. Thus, MIMO channel estimation is considered as a major barrier towards practical realization of 1-bit ADC MIMO system. In this paper, two efficient sparsity-based channel estimation techniques are proposed for 1-bit ADC MIMO systems, namely the low complexity sparsity-based channel estimation(LCsCE), and the iterative adaptive sparsity channel estimation(IAsCE). In these techniques, the sparsity of the 1-bit ADC MIMO channel is exploited to propose a new adaptive and iterative compressive sensing(Cs) recovery algorithm to handle the 1-bit ADC quantization effect. The proposed algorithms are tested with the state-of-the-art 1-bit ADC MIMO constant envelope modulation(MIMO-CEM). The 1-bit ADC MIMO-CEM system is chosen as it fulfills both energy and hardware complexity constraints of the IoT PHY layer. simulation results reveal the high effectiveness of the proposed algorithms in terms of spectral efficiency(sE) and computational complexity. The proposed LCsCE reduces the computational complexity of the 1-bit ADC MIMO-CEM channel estimation by 86%, while the IAsCE reduces it by 96% compared to the recent techniques of MIMO-CEM channel estimation. Moreover, the proposed LCsCE and IAsCE improve the spectrum efficiency by 76 % and 73 %, respectively, compared to the recent techniques.

关键词： channel estimation 1-bit ADC MIMO sparsity recovery compressive sensing Internet of things

Nucleoside modified mRNA-lipid nanoparticles as a new delivery platform for the repair of the injured spinal cord

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Neural Regeneration Research 2025年第8期20卷 2311-2312页

作者： Krisztián Pajer Tamás Bellák Antal Nógrádi Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary

spinal cord injury and treatment opportunities:The adult mammalian spinal cord has a very limited capacity for spontaneous regeneration due to various intrinsic molecular and cellular *** the spinal cord neurons have the capacity to regenerate their axons,the expression of growth inhibitory factors,lack or suppression of proper guidance cues,and profound inflammatory responses do not permit successful regeneration(Khyeam et al.,2021).

关键词： injured capacity modified

Novel synthesis of some Phthalazinone Derivatives

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Chinese Journal of Chemistry 2011年第7期29卷 1446-1450页

作者： mahmoud, mahmoud R. Abou-Elmagd, Wael s.I. Derbala, Hamed A. Hekal, Mohamed H. Chemistry Department Faculty of Science Ain Shams University Abassia 11566 Cairo Egypt

Dimethyl homophthalate condensed with isatin to give the unexpected five membered lactone 3 rather than the half ester 1 and the β-lactone 2. Treatment of compound 3 with excess hydrazine hydrate afforded phthalazinone carbohydrazide 4 which represents a novel method for the synthesis of phthalazinone derivatives. The carhohy- drazide 4 upon treatment with carbon disulphide afforded 1,3,4-oxadiazole derivative 5, which reacted with ethyl- chloroacetate to give the s-alkylated product 6. The structure of compound 3 compared with 2 was discussed using hyperchem professional （7） AM1 calculations, X-ray single crystal structure and complete spectral data.

关键词： phthalazinone carbohydrazide oxadiazole triazolo oxadiazole AMx calculation condensation

Theoretical work on magnetocaloric effect in La_(0.75)Ca_(0.25)MnO_(3)

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Journal of Advanced Ceramics 2012年第4期1卷 290-295页

作者： mahmoud Aly HAMAD Physics Department College of ScienceAl-Jouf UniversityAl-JoufSkakaP.O.Box 2014Saudi Arabia

In this work,a phenomenological model is applied to describe the magnetocaloric effect for the La_(0.75)Ca_(0.25)MnO_(3)system near a second-order phase transition from a ferromagnetic to a paramagnetic *** on this model,it can predict the values of the magnetocaloric properties from calculation of magnetization as a function of temperature under different external magnetic *** magnetic entropy change reaches a peak of about 5.39 J/(kg·K)at 257 K upon 4 T applied field ***ΔsM distribution is much more uniform than that of gadolinium,which is desirable for an Ericson-cycle magnetic refrigerator.

关键词： magnetocaloric effect model magnetic entropy change heat capacity change relative cooling power

Design of a Bio-inspired Hull shape for an AUV from Hydrodynamic stability Point of View through Experiment and Numerical Analysis

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Journal of Bionic Engineering 2018年第6期15卷 950-959页

作者： Amir Honaryar mahmoud Ghiasi Faculty of Marine Technology Amirkabir University of Technology Hafez Avenue 15875-4413 Tehran Iran

The hydrodynamic characteristics and body shape of catfish, Hypostomus, are used to design and develop an Autonomous Under- water Vehicle （AUV） named ZRAUV for subsea pipeline and cable inspection. Among the hydrodynamic characteristics, stability of this bio-inspired AUV, which may be adversely affected by disturbances such as marine currents during inspection process, is taken into consideration and evaluated both numerically and experimentally. Concerning numerical investigation, computational fluid dynamics based on Reynolds Averaged Navier-stokes equations are applied to compute the hydrodynamic damping derivatives needed for stability analysis. In order to verify the numerical predictions, computations are also performed for the well-known submarine body with a typical axisymmetric hull shape, sUBOFF. Experiments are also carried out for both proposed AUV and a conventional axisymmetric one using self-propulsion tests. Measurements of turning rate in turning circle maneuver are in reasonably good agreement with those of numerical estimations and indicate that the turning rate of conventional bodies like sUBOFF is approximately 3.8 times as great as that of bio-inspired AUV. In other words, the findings reveal that in comparison with common axisymmetric bodies, the proposed AUV with biological hull shape is more stable by about 99%, thus, it is highly suitable for subsea pipeline and cable inspection.

关键词： catfish hydrodynamic stability bio-inspired AUV hull form computational fluid dynamics

Investigation into the effect of silica nanoparticles on the rheological characteristics of water-in-heavy oil emulsions

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Petroleum science 2019年第6期16卷 1374-1386页

作者： O.s.Alade D.A.Al shehri M.mahmoud Department of Petroleum Engineering College of Petroleum and GeosciencesKing Fahd University of Minerals and PetroleumDhahranSaudi Arabia

The effect of silica nanoparticles on the rheological characteristics of water-in-heavy oil emulsions has been *** oil recovery methods for heavy oil production(most especially,thermal fluid injection)usually result in the formation of water-in-oil(W/O)*** reality,the emulsion produced also contains some fine solid mineral particles such as silica,which,depending on its quantity,may alter the viscosity and/or rheological properties of the fluid.A series of binary-component emulsions were separately prepared by dispersing silica nanoparticles[phase fraction,βs,=0.5%–5.75%(wt/v)]in heavy oil(s/O suspension)and by dispersing water[water cut,θw=10%–53%(v/v)]in heavy oil(W/O emulsion).Ternary-component emulsions comprising heavy oil,water droplets and suspended silica nanoparticles(s/W/O)were also prepared with similar ranges ofθw andβ*** viscosity was measured at different shear rates(5.1–1021.4 s-1)and temperatures(30–70°C).Both binary-component and ternary-component emulsion systems were observed to exhibit nonNewtonian shear thinning *** viscosity of the heavy oil and W/O emulsions increased in the presence of silica *** effect was,however,less signifi cant belowβs=2%(wt/v).Moreover,a generalized correlation has been proposed to predict the viscosity of both binary-component and ternary-component emulsions.

关键词： Heavy oil emulsions Heavy oil–silica nanoparticle suspension Viscosity functions Rheological model Complex fluid

Vascular endothelial growth factor:a double-edged sword in the development of white matter lesions

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Neural Regeneration Research 2025年第1期20卷 191-192页

作者： Narek Manukjan Daniel Fulton Zubair Ahmed WMatthijs Blankesteijn sébastien Foulquier Department of Pharmacology and Toxicology Maastricht UniversityMaastrichtThe Netherlands CARIM-school for Cardiovascular Diseases Maastricht UniversityMaastrichtThe Netherlands Neuroscience and Ophthalmology Institute of Inflammation and AgeingUniversity of BirminghamEdgbastonBirminghamUK Centre for Trauma sciences Research University of BirminghamEdgbastonBirminghamUK MHeNs-school for Mental Health and Neuroscience Maastricht UniversityMaastrichtThe Netherlands Department of Neurology Maastricht University Medical CenterMaastrichtThe Netherlands

As the population ages,the burden of age-related diseases becomes ***,over 55 million people suffer from dementia worldwide,with Alzheimer’s disease being the most common ***,it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease(csVD)may be a more detrimental cause for dementia(Cuadrado-Godia et al.,2018).It is estimated that 10%-30%of the elderly population and 35%-90%of all dementia patients exhibit signs of *** term csVD refers to pathology affecting the small vessels of the brain,which can lead to lacunar cerebral infarcts,enlarged perivascular spaces,and cortical hemorrhages(Cuadrado-Godia et al.,2018).CsVD is often associated with cognitive decline,gait problems,and dementia(Cuadrado-Godia et al.,2018).

关键词： pathology becoming white

Opposite Modulatory Effects of Crataegus aronia Aqueous Extract on Platelet Aggregation in Rats

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Chinese Journal of Integrative Medicine 2021年第9期27卷 696-704页

作者： Abdullah s.shatoor Ali shati s.Al Humayed sultan AL-Qahtani mahmoud Alkhateeb Department of Medicine Cardiology SectionCollege of MedicineKing Khalid UniversityAbha(64121)Saudi Arabia Department of Biology College of ScienceCollege of MedicineKing Khalid UniversityAbha(64121)Saudi Arabia Department of Physiology College of MedicineKing Saud bin Abdulaziz University for Health SciencesRiyadh(11481)Saudi Arabia

Objectives:To reveal the mechanisms behind the dual effects of Crataegus aronia(***)aqueous extract on platelet aggregation by focusing on function,regulation,expression,and signaling of platelets P_(2)Y_(12)***:Adult male Wistar rats(120±10 g)were classified as control received the vehicle,***(200 mg/kg),and ***(2,000 mg/kg)-treated *** treatments for consecutive 7 days,hematological and molecular experiments were conducted to detect alterations in platelet aggregation,thromboxane B2(THXB2)and intracellular reactive oxygen species(ROs)content;protein levels of P_(2)Y_(12),p-Akt,cyclic adenosine monophosphate(c AMP),phosphorylated vasodilator-stimulated-phosphoprotein(p-VAsP),nuclear factorκB(NF-κB),P-selectin,*** platelets were determined by Western blot;m RNA expressions of P_(2)Y_(12)and some inflammatory markers were determined by real-time polymerase chain ***:At a concentration of 200 mg/kg,*** inhibited platelet aggregation through multiple interconnected mechanisms including downregulation P_(2)Y_(12)synthesis and expression,stimulating intracellular cAMP levels and protein levels of p-VAsP,inhibiting platelets THXB2 release and protein levels of ***,it inhibited platelets level of ROs and of NF-κB,a major signaling pathway that stimulates the expression of P_(2)Y_(12)and THXA2 *** findings were seen in platelets of rats received *** at a concentration of 2,000 mg/***,co-administration of N-acetylcysteine prevented all hematological and molecular alterations exerted by the high dose of the extract and inhibited platelet ***:Oral administration of *** at low dose inhibits platelet aggregation by reducing THXB2 release,expression of P-selectin and activating c AMP and Akt signaling through two major mechanisms including downregulation of P_(2)Y_(12)and inhibition of ROs-induced activation of NF-κB,an effect that is observed to be in the

关键词： Crataegus aronia platelets aggregation P_(2)Y_(12) Intracellular cyclic adenosine monophosphate reactive oxygen species nuclear factorκB

Arabic Bank Check Processing: state of the Art

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Journal of Computer science & Technology 2013年第2期28卷 285-299页

作者： Irfan Ahmad sabri A.mahmoud Information and Computer science Department King Fahd University of Petroleum & Minerals

In this paper, we present a general model for Arabic bank check processing indicating the major phases of a check processing system. We then survey the available databases for Arabic bank check processing research. The state of the art in the different phases of Arabic bank check processing is surveyed （i.e., pre-processing, check analysis and segmentation, features extraction, and legal and courtesy amounts recognition）. The open issues for future research are stated and areas that need improvements are presented. To the best of our knowledge, it is the first survey of Arabic bank check processing.

关键词： handwriting analysis document analysis text processing feature evaluation and selection pattern analysis