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In-situ alloyed CoCrFemnNi high entropy alloy:microstructural development in laser powder bed fusion

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Journal of materials Science & Technology 2022年第28期123卷 123-135页

作者： Peng Chen Xiyu Yao moataz m.Attallah ming Yan Department of materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Advanced materials Processing Laboratory University of BirminghamBirmingham B152TTUK

In-situ alloying has the potential to combine the compositional flexibility of high entropy alloys(HEAs)and the advanced forming capability of laser powder bed fusion(LPBF).This study fundamentally investigated the elemental homogenisation and grain development in the in-situ alloying process of CoCrFemnNi HEA,by analysing the basic units,i.e.,tracks and layers,and introducing mn as an alloying element to the base Co Cr Fe Ni *** modelling methods were employed to predict meltpool dimensions,and the results indicated the dependence of the modelling on practical meltpool *** of elemental distribution was found in keyhole meltpools since an intensive flow was generated due to recoil *** homogeneity of in-situ alloyed mn in single tracks was insufficient whether operated in conduction mode or keyhole mode,which required remelting from adjacent tracks and following layers to promote homogenisation *** preferred orientation in single tracks along scanning directions changed fromtoas the scanning speed increased,although the cross-sections were similar in size with identical linear energy *** preference can be inherited during the printing process and lead to different textures in three-layer *** was also observed that applying hatch spacing smaller than a half meltpool width could coarsen the grains in a *** results from this study provide structure-parameter correlations for future microstructural tailoring and manipulation.

关键词： Laser powder bed fusion High entropy alloy In-situ alloying Single track Elemental homogenisation

Does vitamin C have the ability to augment the therapeutic effect of bone marrow-derived mesenchymal stem cells on spinal cord injury？

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Neural Regeneration Research 2017年第12期12卷 2050-2058页

作者： Nesrine Salem mohamed Y.Salem mohammed m.Elmaghrabi moataz A.Elawady mona A.Elawady Dina sabry Ashraf Shamaa Abdel-Haleem H.Elkasapy Noha Ibrhim Azza Elamir Department of Histology and Cell Biology Faculty of Medicine Banha University Banha Egypt Department of Neurosurgery Faculty of Medicine Banha University Banha Egypt Department of Community medicine Faculty of Medicine Banha University Banha Egypt Department of medical Biochemistry Faculty of Medicine Cairo University Giza Egypt Department of Surgery and Radiology Faculty of Veterinary Medicine Cairo University Giza Egypt Department of Surgery Faculty of Veterinary Medicine Banha University Banha Egypt Department of medical Physiology Faculty of Medicine Banha University Banha Egypt Department of medical Biochemistry Faculty of Medicine El Fayoum University Egyptian Egypt

methylprednisolone（mP） is currently the only drug confirmed to exhibit a neuroprotective effect on acute spinal cord injury（SCI）. Vitamin C（VC） is a natural water-soluble antioxidant that exerts neuroprotective effects through eliminating free radical damage to nerve cells. Bone marrow mesenchymal stem cells（BmmSCs）, as multipotent stem cells, are promising candidates in SCI repair. To evaluate the therapeutic effects of mP, VC and BmmSCs on traumatic SCI, 80 adult male rats were randomly divided into seven groups： control, SCI（SCI induction by weight-drop method）, mP（SCI induction, followed by administration of 30 mg/kg mP via the tail vein, once every other 6 hours, for five times）, VC（SCI induction, followed by intraperitoneal administration of 100 mg/kg VC once a day, for 28 days）, mP ＋ VC（SCI induction, followed by administration of mP and VC as the former）, BmmSCs（SCI induction, followed by injection of 3 × 10~6 BmmSCs at the injury site）, and BmmSCs ＋ VC（SCI induction, followed by BmmSCs injection and VC administration as the former）. Locomotor recovery was assessed using the Basso mouse Scale. Injured spinal cord tissue was evaluated using hematoxylin-eosin staining and immunohistochemical staining. Expression of transforming growth factor-beta, tumor necrosis factor-alpha, and matrix metalloproteinase-2 genes was determined using real-time quantitative PCR. BmmSCs intervention better promoted recovery of nerve function of rats with SCI, mitigated nerve cell damage, and decreased expression of transforming growth factor-beta, tumor necrosis factor-alpha, and matrix metalloproteinase-2 genes than mP and/or VC. more importantly, BmmSCs in combination with VC induced more obvious improvements. These results suggest that VC can enhance the neuroprotective effects of BmmSCs against SCI.

关键词： nerve regeneration spinal cord injury vitamin C methylprednisolone bone marrow mesenchymalstern cells locotmotor neural regeneration

Fabricating CoCrFemnNi high entropy alloy via selective laser melting in-situ alloying

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Journal of materials Science & Technology 2020年第8期36卷 40-43页

作者： Peng Chen Sheng Li Yinghao Zhou ming Yan moataz m.Attallah Advanced materials Processing Laboratory University of BirminghamBirmingham B152TTUK Department of materials Science and Engineering and Shenzhen Key Laboratory for Additive Manufacturing of High Performance MaterialsSouthern University of Science and TechnologyShenzhen 518055China

Quasi-equiatomic Co Cr Fe mn Ni high entropy alloy(HEA)has been in-situ alloyed by selective laser melting(SLm)from a blend of Co Cr Fe Ni pre-alloyed powder and mn elemental *** blended powder shows good printability with various SLm parameters and the as-built HEA samples achieve a reliable forming *** the slight evaporation of mn,energy dispersive spectrometer mapping and Xray diffraction results show that the as-built HEA has a homogeneous chemical distribution and presents a single face-centred-cubic(fcc)phase,indicating successful in-situ *** study has verified the feasibility of using blended powder to prepare high-quality HEA by SLm.

关键词： High entropy alloys Laser processing Selective laser melting In-situ alloying CoCrFemnNi Crystal structure

The development of a high-performance Ni-superalloy additively manufactured heat pipe

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Advances in manufacturing 2022年第4期10卷 610-624页

作者： Sheng Li Khamis Essa James Carr States Chiwanga Andrew Norton moataz m.Attallah School of Electromechanical Engineering Guangdong University of TechnologyGuangzhou 510006People’s Republic of China School of Engineering University of BirminghamEdgbastonBirmingham B152TTUK Henry moseley X-ray Imaging Facility Henry Royce Institute for Advanced MaterialsDepartment of MaterialsUniversity of ManchesterManchester M139PLUK European Thermodynamics Ltd 8 Priory Business ParkWistow RoadKibworthLeicestershire LE80RXUK Rolls-Royce plc P.O.Box 31Derby DE248BJUK School of metallurgy and materials University of BirminghamEdgbastonBirmingham B152TTUK

Additively manufacturing(Am)has been used to manufacture fine structures with structured/engineered porosity in heat management *** this study,laser powder bed fusion(LPBF)was used to manufacture a high-performance Ni-superalloy heat pipe,through tailoring LPBF process parameters to fabricate thin wall and *** using novel laser scanning strategies,wick structure heat pipes with maximised surface-area-to-volume ratio,fine features size around 100µm,and controlled porosity were successfully *** and X-ray microtomography(micro-CT)were used to investigate the 3D structure of the void space within the *** test results showed that most of the heat pipes made by LPBF had better performance than the conventionally manufactured *** study also investigated the influences of the process parameters on the porosity volume fraction and the feature *** results showed that LPBF process could fabricate thin structure due to the change of melt pool contact *** relationship between process parameters and bead size reported in this study could help design and manufacture heat pipe with complex fine structure.

关键词： Laser powder bed fusion(LPBF) Heat pipe melt pool microtomography(micro-CT)

ZnO DOPED SODIUm SILICATE PREIONIZE N_(2) LASER

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Chinese Physics Letters 1989年第11期6卷 491-494页

作者： m.montaser F.sabry S.A.Ibrahim hysics Department Faculty of ScienceMonofia UniversityShibin El-koamEgypt Faculty of Science Jordan Univ.of Science and Technology IrbidJordan

An experimental study of the effect of ZnO doped sodium silicate thin film,used as a semiconductive preionizer on the output energy is *** output energy of the nitrogen laser increased by two *** performance of the pr... 详细信息

关键词： LASER film conductive

Silicon micromirrors with three-dimensional curvature enabling lensless efficient coupling of free-space light

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Light(Science & Applications) 2013年第1期2卷 98-106页

作者： Yasser m sabry Bassam Saadany Diaa Khalil Tarik Bourouina Universite Paris-Est ESYCOM(EA 2552)ESIEE ParisF-93162 Noisy-le-GrandFrance Si-Ware Systems 3 Khaled Ibn El-Waleed StreetHeliopolisCairo 11361Egypt Electron.and Comm.Eng.Dept. Faculty of Eng.Ain-Shams UniversityCairoEgypt

miniaturized optical benches process free-space light propagating in-plane with respect to the substrate and have a large variety of applications,including the coupling of light through an optical *** coupling efficiency is usually obtained using assembled micro-optical parts,which considerably increase the system cost and integration *** this work,we report a high coupling efficiency,monolithically integrated silicon micromirror with controlled three-dimensional(3D)curvature that is capable of manipulating optical beams propagating in the plane of the silicon *** on our theoretical modeling,a spherical micromirror with a microscale radius of curvature as small as twice the Gaussian beam Rayleigh range provides a 100%coupling efficiency over a relatively long optical path *** dimensionless parameters facilitates the elucidation of the role of key design parameters,including the mirror’s radii of curvature,independent of the wavelength.A micromachining method is presented for fabricating the 3D micromirror using fluorinated gas *** measured coupling efficiency was greater than 50%over a 200-mm optical path,compared to less than 10%afforded by a conventional flat micromirror,which was in good agreement with the *** the 3D micromirror,an optical cavity was formed with a round-trip diffraction loss of less than 0.4%,resulting in one order of magnitude enhancement in the measured quality factor.A nearly 100%coupling was also estimated when matching the sagittal and tangential radii of curvature of the presented micromirror’s *** reported class of 3D micromirrors may be an advantageous replacement for the optical lenses usually assembled in silicon photonics and optical benches by transforming them into real 3D monolithic systems while achieving wideband high coupling efficiency over submillimeter distances.

关键词： coupling efficiency Gaussian beam coupling micro-optics monolithic chip optical cavity optical fabrication optical benches silicon photonics

Localized Corrosion Behavior of 6% mo Super Austenitic & 316L Stainless Steels in Low pH 3% NaCl Solution

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Journal of materials Science & Technology 2005年第4期21卷 465-469页

作者： m.m.A.Gad H.G.Salem A.m.Nasreldin H.sabry A.A.EI-Sayed metallurgy Department Atomic Energy Authority Cairo EgyptMechanical Engineering Department AUC Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo EgyptEuropean Neighbourhood and Partnership Instrument (ENPI) Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo Egypt

Electrochemical techniques were applied to study the crevice corrosion resistance of two types of stainless steel alloys namely, conventional 316L and 6% mo super austenitic in acidified 3% NaCl solution at room *** results showed that 6% mo alloy possessed a remarkable resistance to crevice corrosion compared with 316L alloy when they are tested in the same solution. The breakdown potential at which passivity broke down for 316L alloy was 0.00 mV （SCE）. The corresponding value for 6% mo alloy could not reach up to the potential value of 700 mV （SCE）. 316L alloy suffered extremely from crevice corrosion at room temperature （about 25℃）, which indicates that the critical crevice corrosion temperature, below which crevice corrosion does not occur, was lower than the test temperature. For 6% mo alloy, the critical crevice corrosion temperature was higher than the testing temperature. Electrochemical parameters indicated that 6% mo alloy exhibited higher crevice corrosion resistance than 316L alloy.

关键词： Crevice corrosion 6% mo super austenitic Conventional 316L Critical crevice temperature

On-chip parallel Fourier transform spectrometer for broadband selective infrared spectral sensing

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microsystems & Nanoengineering 2020年第1期6卷 1267-1275页

作者： Alaa Fathy Yasser m.sabry Sebastien Nazeer Tarik Bourouina Diaa A.Khalil Faculty of Engineering Ain-Shams University1 Elsarayat St.AbbassiaCairoEgypt Si-Ware Systems 3 Khalid Ibn Al-Waleed St.HeliopolisCairoEgypt UniversitéParis-Est ESYCOM EA 2552ESIEE Paris93162 Noisy-le-GrandFrance

Optical spectrometers enable contactless chemical ***,decreasing both their size and cost appears to be a prerequisite to their widespread ***-scale implementation of optical spectrometers still requires tackling two main ***,operation over a broad spectral range extending to the infrared is required to enable covering the molecular absorption spectrum of a broad variety of *** is addressed in our work with an micro-Electro mechanical Systems(mEmS)-based Fourier transform infrared spectrometer with an embedded movable micro-mirror on a silicon ***,fine spectral resolutionΔλis also required to facilitate screening over several chemicals.A fundamental limit states thatΔλis inversely proportional to the mirror motion range,which cannot exceed the chip *** boost the spectral resolution beyond this limit,we propose the concept of parallel(or multi-core)FTIR,where multiple interferometers provide complementary optical paths using the same actuator and within the same *** concept scalability is validated with 4 interferometers,leading to approximately 3 times better spectral *** the atmospheric contents of a greenhouse gas are monitored,the methane absorption bands are successfully measured and discriminated using the presented device.

关键词： interferometer spectral mirror

Product Spacing of Stress–Strength under Progressive Hybrid Censored for Exponentiated-Gumbel Distribution

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Computers, materials & Continua 2021年第3期66卷 2973-2995页

作者： R.Alshenawy mohamed A.H.sabry Ehab m.Almetwally Hisham m.Elomngy Department of mathematics and Statistics King Faisal UniversityAl-Ahsa31982Saudi Arabia Department of Applied Statistics and Insurance Mansoura UniversityMansoura35516Egypt Department of mathematical Statistics Cairo UniversityCairo12613Egypt Department of Statistics Delta University for Science and TechnologyMansoura11152Egypt

maximum product spacing for stress–strength model based on progressive Type-II hybrid censored samples with different cases has been *** paper deals with estimation of the stress strength reliability model R=P(Ymbel distribution random variables with different shape parameters but having the same scale *** stress–strength reliability model is estimated under progressive Type-II hybrid censoring *** progressive Type-II hybrid censoring schemes were used,Case I:A sample size of stress is the equal sample size of strength,and same time of hybrid censoring,the product of spacing function under progressive Type-II hybrid censoring *** II:The sample size of stress is a different sample size of strength,in which the life-testing experiment with a progressive censoring scheme is terminated at a random time T 2 e0;*** maximum likelihood estimation and maximum product spacing estimation methods under progressive Type-II hybrid censored samples for the stress strength model have been discussed.A comparison study with classical methods as the maximum likelihood estimation method is ***,to compare the performance of various cases,markov chain monte Carlo simulation is conducted by using iterative procedures as Newton Raphson or conjugate-gradient ***,two real datasets are analyzed for illustrative purposes,first data for the breaking strengths of jute fiber,and the second data for the waiting times before the service of the customers of two banks.

关键词： Exponentiated Gumbel distribution stress-strength model progressive Type-II hybrid censoring maximum product spacing maximum likelihood