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Photonic Sensors 2020年第1期10卷 34-44页

作者： Wan Insaniah Saleha ahmad SHAH ahmad Fairuz omar School of Physics Universiti Sains Malaysia11800 USMPenangMalaysia

Gafchromic external beam therapy 3(EBT3)film has widely been used in medical field ***,the EBT3 film’s color gradually changes from light green to darker color under incremental exposures by ionizing or even non-ionizing ultraviolet(UV)*** absorbance of the EBT3 film can be used to predict absorbed doses by the ***,until today,related researches still rely on spectrometers for color analysis of EBT3 ***,this paper presents a comparative analysis between results produced by the spectrometer and a much simpler light-emitting diode-photodiode based system in profiling the color changes of EBT3 films after exposure by solar UV *** work has been conducted on a set of 50 EBT3 samples with incremental solar UV exposure(doses).The wavelength in the red region has the best sensitivity in profiling the color changes of EBT3 films for low solar UV exposure *** study foresees the ability of blue wavelength to profile films with a large range of solar UV *** LED(light emitting diode)-based optical system has produced comparable measurement accuracies to the spectrometer and thus,with a potential for replacing the need for a multipurpose spectroscopy system for simple measurement of light attenuation.

关键词： External beam therapy 3 light emitting diode solar ultraviolet visible absorbance spectroscopy

Specialized Optical Fiber Sensor for Nondestructive Intrinsic Quality Measurement of Averrhoa Carambola

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Photonic Sensors 2013年第3期3卷 272-282页

作者： ahmad Fairuz omar Mohd Zubir MATJAFRI School of Physics Universiti Sains Malaysia 11800 Penang Malaysia

This paper presents an innovative and low-cost approach for nondestructive fruit quality analysis. The specialized optical fiber sensor developed and presented in this paper used a monochromatic wavelength, rather than a broad spectrum, to measure the intact carambola （star fruit） intrinsic quality, namely pH and firmness. The main objective of this research was to investigate the two optical fiber sensors used in this work, namely, the optical fiber red system （OF-RS） that operated with the peak sensitivity at 635 nm and the optical fiber near the infrared spectroscopy system （OF-NIRS） that operated with the peak sensitivity at 880nm. Both systems showed good accuracy in the pH and firmness measurement of the intact carambola with the correlation coefficient R over 0.75, and the measurement results were comparable with those of the commercial spectrometer. The best measurement results were obtained using OF-RS （pH： R = 0.876; the root mean square error （RMSE） = 0.211 pH; firmness： R = 0.872; RMSE = 0.909 kgf）.

关键词： Carambola firmness optical fiber sensor pH quality

Mixed phase sodium manganese oxide as cathode for enhanced aqueous zinc-ion storage

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2214-2220页

作者： Xinyu Wang Xinghua Qin Qiongqiong Lu Mingming Han ahmad omar Daria Mikhailova Institute of Materials and Technology Dalian Maritime UniversityDalian 116026China Leibniz Institute for Solid State and Materials Research(IFW)Dresden e.V. Helmholtzstraße 2001069 DresdenGermany School of Materials Science and Engineering Central South UniversityChangsha 410083China

Aqueous zinc-ion batteries have been regarded as a promising alternative to large-scale energy storage, due to associated low-cost, improved safety and environmental friendliness. However, a high-performance cathode material for both rate capability and specific capacity is still a challenge. One kind of the more promising candidates are sodium manganese oxide(NMO) materials, although they suffer from individual issues and need to be further improved. Herein, we present a novel mixed phase NMO material composed of nearly equal amounts of Na(0.55)Mn2O4 and Na(0.7)MnO(2.05). The structured configuration with particle size of 200–500 nm is found to be beneficial towards improving the ion diffusion rate during the charge/discharge process. Compared with Na(0.7)MnO(2.05) and Na(0.55)Mn2O4, the mixed phase NMO demonstrates an enhanced rate capability and excellent long-term cycling stability with a capacity retention of 83% after 800 cycles. More importantly, the system also delivers an impressive energy density and power density, as 378 W·h·kg^-1 at 68.7 W·kg^-1, or 172 W·h·kg^-1 at 1705 W·kg^-1. The superior electrochemical performance is ascribed to the fast Zn^2+ diffusion rate because of a large ratio of capacitive contribution(63.9% at 0.9 m V·s^-1). Thus, the mixed phase route provides a novel strategy to enhance electrochemical performance, enabling mixed phase NMO as very promising material towards large-scale energy-storage applications.

关键词： Aqueous zinc-ion battery Sodium manganese oxide Mixed phase High energy density

Freestanding strontium vanadate/carbon nanotube films for long-life aqueous zinc-ion batteries

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Rare Metals 2022年第2期41卷 415-424页

作者： Ye-Hong Du Xian-Yu Liu Xin-Yu Wang Jun-Cai Sun Qiong-Qiong Lu Jian-Zhi Wang ahmad omar Daria Mikhailova Institute of Materials and Technology Dalian Maritime UniversityDalian 116026China e-mail:wangxinyu@*** School of Chemistry and Chemical Engineering Lanzhou City UniversityLanzhou 730070China Leibniz Institute for Solid State and Materials Research(IFW)Dresden E.V Helmholtzstraße 2001069 DresdenGermany e-mail:q.lu@ifw-dresden.de Key Laboratory for Green Chemical Process of Ministry of Education School of Chemical Engineering and PharmacyWuhan Institute of TechnologyWuhan 430205China

Aqueous rechargeable zinc-ion battery(ZIB)is considered to be a potential energy storage system for large-scale applications due to its environmental friendliness,high safety,and low ***,it remains challenging to develop suitable cathode materials with high specific capacity and long-term cyclic ***,we have fabricated freestanding Sr0.19V2O51.3H2O/carbon nanotubes(SrVO/CNTs)composite films with different mass ratios by incorporating SrVO into CNTs *** synthesized SrVO possesses a large interlayer spacing of 1.31 nm,which facilitates Zn(2+)***,the SrVO/CNTs composite film with conductive network structure promotes electron transfer and ensures good contact between SrVO and CNTs during the long-term cycling *** a result,the battery based on the SrVO/CNTs composite cathode with a mass ratio of 7:3 delivers a specific capacity of 326 mAh·g^(-1)at 0.1 A·g^(-1)and 145 mAh·g^(-1)at 5 A·g^(-1),demonstrating a high capacity and excellent rate ***,the assembled ZIB shows good capacity retention of 91%even after ultra-long cycling for 7500 cycles at a high current rate of 5 Ag^(-1).More importantly,the battery also delivers a high energy density and power density,as 290 Wh·kg^(-1)at 125 W·kg^(-1)(0.1 A·g^(-1)),or 115 Wh·kg^(-1)at 6078 W·kg^(-1)(5 Ag^(-1)).The results demonstrate that the SrVO/CNTs composite is a promising cathode toward large-scale energy storage applications.

关键词： Aqueous zinc-ion battery Strontium vanadate Carbon nanotubes network Freestanding composite film Long cycle life

Evaluation of hand infections in the emergency department using point-of-care ultrasound

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World Journal of Emergency Medicine 2024年第4期15卷 283-288页

作者： David ahmad Haidar David Mintz Brandon M Wubben omar Rizvi Srikar Adhikari Department of Emergency Medicine Michigan MedicineAnn Arbor 48109-1382USA University of Arizona College of Medicine Tucson 85724USA Department of Emergency Medicine University of IowaIowa City 52242-1009USA Department of Surgery University of Arizona College of MedicineTucson 85724USA Department of Emergency Medicine University of Arizona College of MedicineTucson 85724USA

BACKGROUND:We aimed to evaluate the utility of point-of-care ultrasound(POCUS)in the assessment of hand infections that present to the emergency department(ED)and its impact on medical decision making and patient ***:We conducted a retrospective review of patients who presented to two urban academic EDs with clinical presentations concerning for skin and soft tissue infections(SSTI)of the hand between December 2015 and December *** trained POCUS fellowship physicians reviewed an ED POCUS database for POCUS examinations of the *** then reviewed patients’electronic health records(EHR)for demographic characteristics,history,physical examination findings,ED course,additional imaging studies,consultations,impact of POCUS on patient care and final ***:We included a total of 50 cases(28 male,22 female)in the final *** most common presenting symptoms and exam findings were pain(100%),swelling(90%),and erythema(74%).The most common sonographic findings were edema(76%),soft tissue swelling(78%),and fluid surrounding the tendon(57%).POCUS was used in medical decision making 68%of the time(n=34),with the use of POCUS leading to changes in management 38%of the time(n=19).POCUS use led to early antibiotic use(11/19),early consultation(10/19),and led to the performance of a required procedure(8/19).The POCUS diagnosis was consistent with the discharge diagnosis of flexor tenosynovitis 8/12 times,abscess 12/16 times,and cellulitis 14/20 ***:POCUS is beneficial for evaluating of hand infections that present to the ED and can be used as an important part of medical decision making to expedite patient care.

关键词： Ultrasound Point-of-care ultrasound Cellulitis Abscess Flexor tenosynovitis

Carbon materials for stable Li metal anodes: Challenges, solutions, and outlook

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Carbon Energy 2021年第6期3卷 957-975页

作者： Qiongqiong Lu Yulin Jie Xiangqi Meng ahmad omar Daria Mikhailova Ruiguo Cao Shuhong Jiao Yan Lu Yaolin Xu Leibniz Institute for Solid State and Materials Research(IFW)Dresden e.V. DresdenGermany Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy ConversionDepartment of Materials Science and EngineeringUniversity of Science and Technology of ChinaHefeiChina Department of Electrochemical Energy Storage Helmholtz-Zentrum Berlin für Materialien und Energie(HZB)BerlinGermany Institute of Chemistry University of PotsdamPotsdamGermany

Lithium(Li)metal is regarded as the ultimate anode for next-generation Li-ion batteries due to its highest specific capacity and lowest electrochemical ***,the Li metal anode has limitations,including virtually infinite volume change,nonuniform Li deposition,and an unstable electrode-electrolyte interface,which lead to rapid capacity degradation and poor cycling stability,significantly hindering its practical *** address these issues,intensive efforts have been devoted toward accommodating and guiding Li deposition as well as stabilizing the interface using various carbon materials,which have demonstrated excellent effectiveness,benefiting from their vast variety and excellent tunability of the structure-property *** review is intended as a guide through the fundamental challenges of Li metal anodes to the corresponding solutions utilizing carbon *** specific functionalities and mechanisms of carbon materials for stabilizing Li metal anodes in these solutions are discussed in *** from the stabilization of the Li metal anode in liquid electrolytes,attention has also been paid to the review of anode-free Li metal batteries and solid-state batteries enabled by strategies based on carbon ***,we have reviewed the unresolved challenges and presented our outlook on the implementation of carbon materials for stabilizing Li metal anodes in practical applications.

关键词： carbon materials interface engineering Li deposition regulation Li metal anode structure stabilization

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自支撑碳基柔性超级电容器电极材料研究进展

新型炭材料（中英文） 2022年第5期37卷 875-897页

作者：赵一蓉刘聪聪卢琼琼 omar ahmad 潘孝军 MIKHAILOVA Daria 兰州大学物理科学与技术学院甘肃兰州730000 Leibniz Institute for Solid State and Materials Research(IFW)Dresden e.V. Dresden.01069

为了驱动柔性电子设备和传感器工作,急需探索具有高电化学性能和优异力学性能的柔性超级电容器。自支撑电极在柔性超级电容器中起着至关重要的作用。独立自支撑碳基电极因其高导电性、重量轻、孔隙率可调、表面积可调、易于功能化和优... 详细信息

为了驱动柔性电子设备和传感器工作,急需探索具有高电化学性能和优异力学性能的柔性超级电容器。自支撑电极在柔性超级电容器中起着至关重要的作用。独立自支撑碳基电极因其高导电性、重量轻、孔隙率可调、表面积可调、易于功能化和优异的力学性能而被广泛应用于柔性超级电容器。此外,碳基电极还具有来源丰富,成本低廉等优势。本综述系统总结了基于各种炭材料的独立自支撑碳基电极在柔性超级电容器中的最新进展,并讨论了独立自支撑碳基电极在柔性超级电容器商业化过程中的挑战和未来机遇。

关键词：炭材料赝电容自支撑电极柔性超级电容器

Ultrasmall CoS nanoparticles embedded in heteroatom-doped carbon for sodium-ion batteries and mechanism explorations via synchrotron X-ray techniques

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Journal of Energy Chemistry 2023年第4期79卷 373-381页

作者： Congcong Liu Qiongqiong Lu Mikhail V.Gorbunov ahmad omar Ignacio G.Gonzalez Martinez Panpan Zhao Martin Hantusch Antonius Dimas Chandra Permana Huanyu He Nikolai Gaponik Daria Mikhailova Leibniz Institute for Solid State and Materials Research(IFW)Dresden e.V. Helmholtzstraße 2001069 DresdenGermany Inorganic Chemistry II Technische Universität DresdenBergstraße 6601069 DresdenGermany Physical Chemistry Technische Universität DresdenZellescher Weg 1901069 DresdenGermany

Transition metal sulfides have been regarded as promising anode materials for sodium-ion batteries(SIB).However,they face the challenges of poor electronic conductivity and large volume change,which result in capacity fade and low rate *** this work,a composite containing ultrasmall CoS(~7 nm)nanoparticles embedded in heteroatom(N,S,and O)-doped carbon was synthesized by an efficient one-step sulfidation process using a Co(Salen)*** ultrasmall CoS nanoparticles are beneficial for mechanical stability and shortening Na-ions diffusion ***,the N,S,and O-doped defect-rich carbon provides a robust and highly conductive framework enriched with active sites for sodium storage as well as mitigates volume expansion and polysulfide *** anode for SIB,CoS@HDC exhibits a high initial capacity of 906 mA h g^(-1)at 100 mA g^(-1)and a stable long-term cycling life with over 1000 cycles at 500 mA g^(-1),showing a reversible capacity of 330 mA h g^(-1).Meanwhile,the CoS@HDC anode is proven to maintain its structural integrity and compositional reversibility during ***,Na-ion full batteries based on the CoS@HDC anode and Na_(3)V_(2)(PO_(4))_(3)cathode demonstrate a stable cycling behavior with a reversible specific capacity of~200 m A h g^(-1)at least for 100 ***,advanced synchrotron operando X-ray diffraction,ex-situ X-ray absorption spectroscopy,and comprehensive electrochemical tests reveal the structural transformation and the Co coordination chemistry evolution of the CoS@HDC during cycling,providing fundamental insights into the sodium storage mechanism.

关键词： Sodium-ion batteries Cobalt sulfide nanoparticles Heteroatom-doped porous carbon matrix Synchrotron X-ray techniques Reaction mechanisms

Freestanding MXene-based macroforms for electrochemical energy storage applications

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SusMat 2023年第4期3卷 471-497页

作者： Qiongqiong Lu Congcong Liu Yirong Zhao Wengao Pan Kun Xie Pengfei Yue Guoshang Zhang ahmad omar Lixiang Liu Minghao Yu Daria Mikhailova Institute of Materials Henan Key Laboratory of Advanced Conductor MaterialsHenan Academy of SciencesZhengzhouHenanChina Leibniz Institute for Solid State and Materials Research(IFW)Dresden e.V. DresdenGermany School of Physical Science and Technology Lanzhou UniversityLanzhouChina School of Engineering Westlake UniversityHangzhouZhejiangChina Faculty of Chemistry and Food Chemistry&Center for Advancing Electronics Dresden Technische Universität DresdenDresdenGermany

Freestanding MXene-based macroforms have gained significant attention as versatile components in electrochemical energy storage applications owing to their interconnected conductive network,strong mechanical strength,and customizable surface chemistries derived from MXene *** comprehensive review article encompasses key aspects related to the synthesis of MXene nanosheets,strategies for structure design and surface medication,surface modification,and the diverse fabrication methods employed to create freestanding MXene-based macroform *** review also delves into the recent advancements in utilizing freestanding MXene macroforms for electrochemical energy storage applications,offering a detailed discussion on the significant progress achieved thus ***,the correlation between the macroform’s structural attributes and its performance characteristics is thoroughly explored,shedding light on the critical factors influencing efficiency and *** the remarkable development,the review also highlights the existing challenges and presents future perspectives for freestanding MXenebased macroforms in the realms of high-performance energy storage *** addressing these challenges and leveraging emerging opportunities,the potential of freestanding MXene-based macroforms can be harnessed to enable groundbreaking advancements in the field of energy storage.

关键词： batteries electrochemical energy storage freestanding macroforms MXenes supercapacitors

Finite element analysis and experimental validation of polymer-metal contacts in block-on-ring configuration

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Friction 2024年第3期12卷 554-568页

作者： K.Y.Eayal AWWAD Khosro FALLAHNEZHAD B.F.YOUSIF ahmad MOSTAFA omar ALAJARMEH A.SHALWAN Xuesen ZENG Mechanical Engineering Department Faculty of EngineeringTafila Technical UniversityTafila 66110Jordan Medical Device Research Institute College of Science and EngineeringFlinders UniversitySouth Australia 5042Australia Centre for Future Materials University of Southern QueenslandToowoomba 4350Australia Department of Manufacturing Engineering Technology Public Authority for Applied Education and TrainingKuwait 13092Kuwait

The wear profile analysis,obtained by different tribometers,is essential to characterise the wear ***,most of the available methods did not take the stress distribution over the wear profile in consideration,which causes inaccurate *** this study,the wear profile of polymer–metal contact,obtained by block-on-ring configuration under dry sliding conditions,was analysed using finite element modelling(FEM)and experimental ***’s wear equation was integrated into a developed FORTRAN-UMESHMOTION code linked with Abaqus software.A varying wear coefficient(k)values covering both running-in and steady state regions,and a range of applied loads involving both mild and severe wear regions were measured and implemented in the *** FEM was in good agreement with the *** model reproduced the stress distribution profiles under variable testing conditions,while their values were affected by the sliding direction and maximum wear depth(hmax).The largest area of the wear profile,exposed to the average contact stresses,is defined as the normal *** the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal *** wear profile was mapped to identify the critical zone where the stress concentration is the key point in this *** surface features were examined in different regions using scanning electron microscope(SEM).Ultimately,SEM analysis showed severer damage features in the critical zone than that in the normal zone as proven by ***,the literature data presented and considered the wear features the same at any point of the wear *** this study,the normal zone was determined at a stress value of about 0.5 MPa,whereas the critical zone was at about 5.5 *** wear behaviour of these two zones showed totally different features from one another.

关键词： polymer-to-metal contact block-on-ring wear profile wear model